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Female canary mate preferences: Differential use of information from two types of male-male interaction
Abstract
During mate choice, females can assess male quality by sampling one male after the other or by paying attention to the outcomes of maleemale interactions. The latter strategy, called eavesdropping, allows fe- males access to information about males’ relative quality and therefore reduces the time, energy and other costs associated with searching for a mate. For oscine females, information can be gathered both by listen- ing to maleemale singing interactions and by visually observing maleemale interactions. To date, how- ever, there has been no comparison of the subsequent behaviour of females according to the specific type of information (acoustic or visual) gathered from maleemale interactions. In two successive experi- ments, we explored how female domestic canaries, Serinus canaria, use visual and acoustic information ob- tained from a maleemale interaction to direct their sexual behaviour. We found that, whereas females preferred the overlapping song of a singing interaction, they avoided the winner of a physical contest over food. The function and range of signals used in these two types of maleemale competition may ac- count for this discrepancy. Timing of song during countersinging is the expression of ritualized dominance relationships using a long-range secondary sexual trait, whereas threat displays used in food competition are not secondary sexual traits and are potentially harmful at close proximity. The timing of song during countersinging seems to be a more important cue for females than dominance over food in determining their sexual behaviour.
... In many territorial songbirds males engage in singing interactions and such vocal interactions are particularly well suited for eavesdropping, as acoustic signals travel some distance and thus allow others to eavesdrop and gain information without risking close-range interactions Todt & Naguib, 2000). Several studies have shown that both male (Akçay, Tom, Campbell, & Beecher, 2013;Naguib & Todt, 1997;Peake, Terry, McGregor, & Dabelsteen, 2001;Sprau, Roth, Amrhein, & Naguib, 2012) and female (Amy et al., 2008;Garcia-Fernandez, Amy, Lacroix, Malacarne, & Leboucher, 2010;Mennill et al., 2002;Otter et al., 1999) songbirds eavesdrop on such interactions. ...
... 'Losing' or 'winning' an interaction did not, however, influence paternity in the broods of low-ranking males (Mennill, Boag, & Ratcliffe, 2003;Mennill et al., 2002). Female domestic canaries, Serinus canaria, showed a preference for males that more frequently overlapped their opponent's song and performed more copulation solicitation displays when exposed to song they previously heard to be the overlapping song in an interaction (Amy et al., 2008;Leboucher & Pallot, 2004). Females stimulated with song of an overlapping male also laid eggs with a higher yolk content than females that were exposed to song that had previously been overlapped by another male. ...
... The controversy, in part, may stem from different authors using the term 'aggressive' in different ways: song overlapping might not be used as an aggressive signal predicting attack during close-range conflicts but instead could be more relevant at an earlier level of escalation such as during longdistance interactions or when no other information is available (Naguib et al., 2011). Regardless of whether song overlap and persistence indicate a more threatening intruder in all contexts, there is ample evidence that females eavesdrop on male vocal interactions and use information gained by eavesdropping to (re)assess the quality of males relative to others and alter their reproductive decisions accordingly (Amy et al., 2008;Garcia-Fernandez et al., 2010;Mennill et al., 2002;Otter et al., 1999). However, we found no evidence that female great tits changed their foraying behaviour into other territories or their investment in clutches and brood attendance. ...
p>Observing interactions between others can provide important information to individuals. Male songbirds often engage in singing contests where they vary the type and timing of signals and provide eavesdropping individuals with information about their competitiveness. How this information is used and its effect on subsequent spatial behaviour and reproductive decisions of eavesdroppers is not well understood. Here we tested whether great tits use information gathered by eavesdropping on male singing interactions to assess rivals and (potential) mates. We used interactive playback experiments to engage territorial males in song contests with either a more (song overlapping and more persistent singing) or less challenging (song alternating and less persistent singing) intruder. We followed male and female movements by automated radiotracking, determined paternity using microsatellite analysis and maternal investment by quantifying egg weights and provisioning behaviour. We expected that mates of males exposed to the challenging treatment would subsequently foray more often off territory to assess other males and potential extrapair mates and invest less in their broods. Moreover, we expected that neighbours would adjust their foraying behaviour according to information gained by eavesdropping. Females, however, did not alter their foraying behaviour or brood investment and neither female nor male neighbours changed their visiting behaviour to playback territories. Our results provide no evidence that females used information gathered by eavesdropping on asymmetric song interactions in reproductive decisions or that song interactions affected movements across territories in the neighbourhood. Overlapping or singing for a longer time on an intruded upon territory may not always be perceived as a higher level of threat, and reproductive decisions and assessment of familiar individuals are likely to be based on multiple sources of information rather than on a single interaction.</p
... To sum up, under a stimulating light schedule, female domestic canaries naturally exhibit sexual responsiveness during a short period bounded by estradiol and progesterone surges around the laying period. Females' choice and selectivity are also related to the development of the reproductive cycle: females were found to be more discriminative during the 3 days preceding the laying of the first egg when sexual motivation is high (Amy et al., 2008). ...
... Overlapping interactions provided information to females about the relative quality or motivation of the singers, whereas alternated interactions did not allow females to identify hierarchical relationships between the two singers (Peake, 2005). Results showed that females preferred the song previously heard as the overlapping one (Fig. 6); when females heard an alternated interaction, they subsequently did not show a preference for either of the two songs (Amy et al., 2008). ...
... Females who had previously seen a competition between two males spent more time near the loser of the competition than near the winner (Amy et al., 2008). These results are congruent with those in the Japanese quails, where females that visually ''eavesdropped'' on fighting males prefer losers to winners (Ophir and Galef, 2003). ...
Birdsong in oscine birds serves both intrasexual and intersexual functions. The aim of this chapter is to contribute to a better understanding of how birdsong is involved in female reproductive activity using the domestic canary as a model. Some special song phrases containing bipartite syllables composed of abrupt frequency falls and short silences (sexy phrases) appear to be particularly efficient to elicit sexual responses. Females canaries seem predisposed to prefer sexy phrases even though early or adult acoustic experience can affect this phenomenon. Moreover, eavesdropping on singing interactions, previous reproductive experience, as well as physical condition may be involved in shaping females’ preferences. Repeated exposures to male sexy phrases during reproduction do not influence the development of nest building or egg laying but affect egg quality. From the sender perspective, the production of the complex sexy phrases needs particular skills from the peripheral motor level as well as the central nervous system level.
... nightingale, Luscinia megarhynchos [3,4]; fighting fish, Betta splendens [5]; great tit, Parus major [6]; domestic canary, Serinus canaria [7,8]). Females also seem to evaluate potential sexual partners by eavesdropping both during the initial stages of mate choice (fighting fish [9]; Japanese quail, Coturnix japonica [10,11]; domestic canary [12,13]) and during extrapair attempts (great tit: [14]; black-capped chickadee, Poecile atricapilla [15]). Thus, the information obtained by eavesdropping can modify the fitness of individuals by influencing the agonistic behaviours an animal undergoes or its reproductive success. ...
... Canaries are socially monogamous [31], they can discriminate their mate from a familiar individual [32] and both wild and domestic canaries have been observed engaging in extra-pair copulations [33] . Furthermore , female canaries eavesdrop on vocal and physical contests between males and use the obtained information to direct their sexual behaviours [12,13]. Although audience effects have never been explored in this species, it is likely that, a least, male-male interactions are modified by the presence of females. ...
... Discussion. This experiment demonstrates that male canaries adjust their extra-pair behaviour to the presence of a social audience, as one could have expected from previous studies [12,13]. Indeed, males courted less in the presence than in the absence of a female in audience and this result could not be explained by the behaviours of the interacting females or by those of the audiences as none of them behaved differently between experimental conditions. ...
Many animals live in a communication network, an environment where individuals can obtain information about competitors or potential mates by observing interactions between conspecifics. In such an environment, interactants might benefit by changing their signalling behaviour in the presence of an audience. This audience effect seems widespread among species, has been observed during various types of interaction (e.g. intra-sexual vs. inter-sexual interaction) and varies according to the social context (e.g. gender, hierarchical or mating status of the audience). However, the way individuals might adapt their signalling behaviour to a combination of these factors remains poorly understood. To address this question, we studied how the presence of an audience affects the behaviour of male domestic canaries Serinus canaria during two types of interactions: (i) an extra-pair interaction and (ii) a male-male competition for food. Males were observed under three conditions: (a) in the absence of audience, (b) in the presence of their mate or (c) of a familiar female. Our results show that male domestic canaries minutely adapt their courting and agonistic behaviours to a combination of: (i) the type of interaction (extra-pair interaction/male-male competition), (ii) the social context (mate, familiar female or nobody in audience) and (iii) the behaviours of both the audience and the interactant. These results highlight the ability of animals to subtly adapt their behaviour to the social environment. This also raises questions about the cognitive foundations and evolution of these processes especially considering that canaries are known neither for having high cognitive abilities nor for being a typical example for the social intelligence hypothesis.
... Female canaries perform more frequent copulation solicitation displays when they are presented with "overlapping" songs relative to "overlapped" songs (Leboucher and Pallot, 2004;Amy et al., 2008). Thus, female preference for overlapping songs may have exerted an evolutionary pressure on males to sing longer-lasting leading songs to outlast a follower song, if what females prefer is which bird outlasts the opponent in the duel. ...
... How duels impact fitness is unclear at this stage. Indeed, although females prefer overlapping singers, they also show a preference for canaries that do not participate in physical contests (Amy et al., 2008). Whether fitness may be related to dueling abilities should further be investigated in wild populations (Bircher et al., 2023). ...
Singing by songbirds is a sexually selected, complex motor skill that is learned during juvenile development. In open-ended learners, adult songs are plastic, that is, birds retain the ability to change their songs. In some seasonal open-ended learners, including canaries, songs become stable at the onset of each breeding season. However, whether context-dependent plasticity of songs occurs during the breeding season remains elusive. We used custom-made telemetric backpack sound recording technology in five groups of canaries to monitor song-based communication from three males in competition for females during the breeding season. This allowed us to record each male’s songs during social interactions. We show that canaries proactively overlap their songs in time during aggressive vocal exchanges that we call duels. Birds that engage in duels take leader or follower roles on a song-to-song basis. When a male canary leads a duel, his songs last longer relative to his solo songs, increasing the chance to outlast the follower’s song. Moreover, the durations of leader and follower songs in duels are correlated, suggesting an interactive online adjustment of their songs. Remarkably, in each group, only two out of the three males extensively engage in duels whereas the third canary rarely participates. Overall, our findings reveal context-dependent behavioral flexibility of male-directed canary song signaling, characterized by a moment-to-moment plasticity different from the slow, well-studied seasonal plasticity. By their context-dependent modulation of the relative timing and duration of vocal exchanges, canary duels offer a window into the social cognitive abilities of songbirds.
... For dominance, boldness and neophobia experiments, birds were food deprived for 1.5 hr. Such a deprivation had no adverse effects on the canaries' health or weight (e.g., Amy et al., 2008;Parisot et al., 2004). Still, as a precaution, experiments were never performed before 10 a.m. ...
... Female domestic canaries generally lay several clutches when placed in Long Days even without a male (e.g., Amy et al., 2008) hormonal state) may explain our results as we did not control for this parameter when the tests were performed in Long Days. ...
Personality traits and behavioural profiles are generally assumed to be stable in adulthood. Yet, it has been hypothesised that animals should cope with cyclical fluctuations by adjusting both single behaviours and suites of behaviour. Photoperiod is well known to induce hormonal and physiological changes, and these changes can in turn affect personality traits and behavioural profiles. This study is the first to explicitly investigate the influence of photoperiod on both behavioural profiles and personality traits. Six potential personality traits (within-flock activity, ability to escape, response to threat, isolation calling, boldness and neophobia) and dominance were measured four times in 96 domestic canaries Serinus canaria (48 males and 48 females): twice during a long photoperiod (Long Days) and 6 months later twice during a short photoperiod (Short Days). Without regard to sex and photoperiod, most traits were highly repeatable, and bolder canaries were more dominant, less sensitive to an external threat and to isolation and less neophobic. In addition, the more active individuals within a flock were the more difficult to catch. Yet, both sex and photoperiod affected personality traits and behavioural profiles. Personality traits remained repeatable within each photoperiod though we observed behavioural plasticity and sex differences for response to threat, neophobia and within-flock activity. Concerning behavioural profiles, the negative relationship between boldness and neophobia remained homogenous in both sexes during Short Days as well as during Long Days. Then, the more active individuals within a flock were the more difficult to catch in Short Days but not in Long Days. Finally, the other correlations not only varied with photoperiod but also with sex. Our study highlights the importance of photoperiod and sex in the expression of personality traits and behavioural profiles, and of the need to measure them across the whole photoperiodic cycle.
... Without risking costly physical interactions, eavesdroppers can obtain absolute and relative information on body condition, fighting ability, and age or experience (Davies & Halliday, 1978;Gil & Gahr, 2002;Halperin, Giri, Elliott, & Dunham, 1998) and adjust their behavior accordingly (Naguib, 2005;Oliveira, McGregor, & Latruffe, 1998;Peake, Terry, McGregor, & Dabelsteen, 2002). In territorial animals, males have been shown to be repelled by male advertisement signals (Krebs, 1977;Nowicki, Searcy, & Hughes, 1998;Sekulic, 1982), while females are expected to be attracted (Amy et al., 2008;Ballentine, Hyman, & Nowicki, 2004;Grafe, 1999;Snedden & Greenfield, 1998) and to use these signals to assess male quality (Bensch & Hasselquist, 1992;Berglund et al., 1996;Byers, Hebets, & Podos, 2010). This dual function of male signaling has however rarely been tested in the same context in one study system. ...
... High-ranking male black-capped chickadees were more likely to lose paternity if their mates had heard them lose a singing contest to a simulated intruder (Mennill et al., 2002), and nightingales that responded stronger to playback were more likely to be mated later in the season (Kunc, Amrhein, & Naguib, 2006). Also, female canaries (Serinus canaria) gave more copulation solicitation displays to a simulated song overlapping male than to an overlapped male (Amy et al., 2008) and male sac-winged bats (Saccopteryx bilineata) sired more offspring if they were stronger territorial singers (Behr et al., 2006). Yet, male great tits that lost simulated territory intrusions were not more often cuckolded by eavesdropping mates, than males that were allowed to win the vocal interaction (Otter et al., 2001). ...
Signals play a key role in the ecology and evolution of animal populations, influencing processes such as sexual selection and conflict resolution. In many species, sexually selected signals have a dual function: attracting mates and repelling rivals. Yet, to what extent males and females under natural conditions differentially respond to such signals remains poorly understood, due to a lack of field studies that simultaneously track both sexes. Using a novel spatial tracking system, we tested whether or not the spatial behavior of male and female great tits (Parus major) changes in relation to the vocal response of a territorial male neighbor to an intruder. We tracked the spatial behavior of male and female great tits (N = 44), 1 hr before and 1 hr after simulating territory intrusions, employing automatized Encounternet radio-tracking technology. We recorded the spatial and vocal response of the challenged males and quantified attraction and repulsion of neighboring males and females to the intrusion site. We additionally quantified the direct proximity network of the challenged male. The strength of a male's vocal response to an intruder induced sex-dependent movements in the neighborhood, via female attraction and male repulsion. Stronger vocal responders were older and in better body condition. The proximity networks of the male vocal responders, including the number of sex-dependent connections and average time spent with connections, however, did not change directly following the intrusion. The effects on neighbor movements suggest that the strength of a male's vocal response can provide relevant social information to both the males and the females in the neighborhood, resulting in both sexes adjusting their spatial behavior in contrasting ways, while the social proximity network remained stable. This study underlines the importance of "silent" eavesdroppers within communication networks for studying the dual functioning and evolution of sexually selected signals.
... In territorial animals, males have been shown to be repelled by male advertisement signals (Krebs, 1977;Nowicki, Searcy, & Hughes, 1998;Sekulic, 1982), while females are expected to be attracted (Amy et al., 2008;Ballentine, Hyman, & Nowicki, 2004;Grafe, 1999;Snedden & Greenfield, 1998) and to use these signals to assess male quality (Bensch & Hasselquist, 1992;Berglund et al., 1996;Byers, Hebets, & Podos, 2010). This dual function of male signaling has however rarely been tested in the same context in one study system. ...
... High-ranking male black-capped chickadees were more likely to lose paternity if their mates had heard them lose a singing contest to a simulated intruder (Mennill et al., 2002), and nightingales that responded stronger to playback were more likely to be mated later in the season (Kunc, Amrhein, & Naguib, 2006). Also, female canaries (Serinus canaria) gave more copulation solicitation displays to a simulated song overlapping male than to an overlapped male (Amy et al., 2008) and male sac-winged bats (Saccopteryx bilineata) sired more offspring if they were stronger territorial singers (Behr et al., 2006). Yet, male great tits that lost simulated territory intrusions were not more often cuckolded by eavesdropping mates, than males that were allowed to win the vocal interaction (Otter et al., 2001). ...
Signals play a key role in the ecology and evolution of animal populations, influencing processes such as sexual selection and conflict resolution. In many species, sexually selected signals have a dual function: attracting mates and repelling rivals. Yet, to what extent males and females under natural conditions differentially respond to such signals remains poorly understood, due to a lack of field studies that simultaneously track both sexes. Using a novel spatial tracking system, we tested whether or not the spatial behavior of male and female great tits (Parus major) changes in relation to the vocal response of a territorial male neighbor to an intruder. We tracked the spatial behavior of male and female great tits (N = 44), 1 hr before and 1 hr after simulating territory intrusions, employing automatized Encounternet radio-tracking technology. We recorded the spatial and vocal response of the challenged males and quantified attraction and repulsion of neighboring males and females to the intrusion site. We additionally quantified the direct proximity network of the challenged male. The strength of a male's vocal response to an intruder induced sex-dependent movements in the neighborhood, via female attraction and male repulsion. Stronger vocal responders were older and in better body condition. The proximity networks of the male vocal responders, including the number of sex-dependent connections and average time spent with connections, however, did not change directly following the intrusion. The effects on neighbor movements suggest that the strength of a male's vocal response can provide relevant social information to both the males and the females in the neighborhood, resulting in both sexes adjusting their spatial behavior in contrasting ways, while the social proximity network remained stable. This study underlines the importance of “silent” eavesdroppers within communication networks for studying the dual functioning and evolution of sexually selected signals.
... To a human observer, male head bobbing resembles the head bobbing observed in other parrot species engaged in BPS. Female sensitivity to male displays is common in birds (e.g., Searcy and Marler, 1981;Borgia, 1995;Forstmeier et al., 2002;Ballentine et al., 2004;Amy et al., 2008;Hoeschele et al., 2010). Thus, it is possible that the apparently repetitive form of male budgerigar displays may underlie the female preference for rhythmic patterns observed in the present experiment. ...
... In particular, it is difficult to distinguish between a preference for hearing a certain acoustic stimulus, and a functional response toward that stimulus. For example, many studies have shown that female mate choice in birds is based on acoustical information derived from male song (e.g., Searcy and Marler, 1981;Forstmeier et al., 2002;Ballentine et al., 2004;Amy et al., 2008;Hoeschele et al., 2010). Does this mean that females prefer to hear attractive male songs over unattractive male songs? ...
A variety of parrot species have recently gained attention as members of a small group of non-human animals that are capable of coordinating their movements in time with a rhythmic pulse. This capacity is highly developed in humans, who display unparalleled sensitivity to musical beats and appear to prefer rhythmically organized sounds in their music. Do parrots also exhibit a preference for rhythmic over arrhythmic sounds? Here, we presented humans and budgerigars (Melopsittacus undulatus) – a small parrot species that have been shown to be able to align movements with a beat – with rhythmic and arrhythmic sound patterns in an acoustic place preference paradigm. Both species were allowed to explore an environment for 5 min. We quantified how much time they spent in proximity to rhythmic vs. arrhythmic stimuli. The results show that humans spent more time with rhythmic stimuli, and also preferred rhythmic stimuli when directly asked in a post-test survey. Budgerigars did not show any such overall preferences. However, further examination of the budgerigar results showed an effect of sex, such that male budgerigars spent more time with arrthymic stimuli, and female budgerigars spent more time with rhythmic stimuli. Our results support the idea that rhythmic information is interesting to budgerigars. We suggest that future investigations into the temporal characteristics of naturalistic social behaviors in budgerigars, such as courtship vocalizations and head-bobbing displays, may help explain the sex difference we observed.
... Differential success in mate competition is a key determinant of fitness for males of many species (Andersson 1994). A male's reproductive rate can be directly affected by his success during contests with other males over females or breeding territory (Leboeuf 1974;Christenson & Goist 1979;McGhee et al. 2007;LaManna & Eason 2011), or indirectly affected as male-male contests can influence the mating preferences of females that eavesdrop on these interactions (Otter et al. 1999;Doutrelant & McGregor 2000;Amy et al. 2008;Aquiloni & Gherardi 2010). Because contests are costly (e.g., Hack 1997;Neat et al. 1998;Briffa & Sneddon 2007), males of many species employ a conditional strategy (see Gross 1996) in which an individual's choice of competitive tactic is influenced by his abilities (e.g., Payne & Pagel 1996), the perceived abilities of his competitor(s) (e.g., Maynard Smith & Parker 1976;Enquist & Leimar 1983;Mesterton-Gibbons 1999), and/or the value of the contested resource (e.g., Enquist & Leimar 1987;Arnott & Elwood 2008). ...
... We propose three potential explanations. First, male fence lizards may overlap (perform a signal to overlap that of a rival) or signal-match (respond to a rival's signal with the same signal) their rival's shudders to convey aggressive intent and/or attract females, as many bird species do (Krebs et al. 1981;Burt et al. 2001;Vehrencamp 2001;Otter et al. 2002;Naguib & Kipper 2006;Naguib & Mennill 2010; but see Smith & Martins 2006) and which may allow females to more easily assess potential mates (Mennill et al. 2002;Amy et al. 2008;Logue & Forstmeier 2008). In support of this, we noted that males not only responded to their rival's shudders by shuddering, but also frequently overlapped their rival's shudders (L. ...
When competing for mates, males of many species use cues from their rivals to evaluate their chances of success. Signaling behavior is a vital component of male–male contests and courtship, and may inform males of a rival's quality or intentions. We used eastern fence lizards (Sceloporus undulatus) to investigate how the time a male spent signaling during mate competition is influenced by his quality, his rival's quality relative to his own, and the value of a contested female. Furthermore, we examined how a male's behavioral response to a competitor's signals would be mediated by his relative quality. We simulated natural encounters by allowing two males to compete over a single female in the laboratory. We measured the time males spent performing two types of displays (pushups and shudders) and categorized male behavioral responses to rival pushup and shudder displays. Time spent signaling was not related to a male's absolute quality (body and head size, condition, and badge sizes), or his quality relative to that of his rival, although males did spend more time performing pushups when competing over females in better condition. Male behavior was also influenced by his rival's signals, such that males of relatively lower quality than their opponents were more likely to aggressively respond to rival pushups and shudders. We discuss these results with respect to the evolution and function of signaling behavior in courtship and male–male contests.
... To test these hypotheses, male music frogs were induced to call in response to playbacks of white noise (WN), HSA or LSA calls with variable inter-stimulus intervals (ISIs). Because female frogs and birds prefer non-overlapped signals (Amy et al. 2008;Martínez-Rivera and Gerhardt 2008) and the precedence effect is an inherent responsive property of the vertebrate auditory system (Zurek 1987;Litovsky et al. 1999), based on our hypotheses we predicted that male music frogs would (1) avoid producing calls which overlapped the occurrence of either WN or conspecific calls, (2) be more likely to call back to HSA than LSA calls, (3) be more likely to produce calls shortly before a playback of conspecific calls since such behavior would provide a competitive advantage and (4) produce calls in response to LSA calls mainly when the ISIs were long, thereby allowing the males to conserve energy for competing more effectively against the HSA calls. ...
... Choosing the optimal timing for displays is a straightforward way to minimize the costs and maximize the probability of mating success (Byrne 2008). Since overlap may obscure the fine temporal components of male calls (Schwartz 1987), females of some species including frogs and birds prefer non-overlapped signals (Amy et al. 2008;Martínez-Rivera and Gerhardt 2008). Therefore, successful males typically produce a greater proportion of their total signaling time free from overlap with the signals of other chorus members compared to unsuccessful males (Schwartz et al. 2001). ...
Male–male vocal competition in anuran species is critical for mating success; however, it is also highly time-consuming, energetically demanding and likely to increase predation risks. Thus, we hypothesized that changes in the social context would cause male vocal competition to change in real time in order to minimize the costs and maximize the benefits of competition. To test this hypothesis, we assessed the effect of repeating playbacks of either white noise (WN) or male advertisement calls on male call production in the Emei music frog (Babina daunchina), a species in which males build mud-retuse burrows and call from within these nests. Previous studies have shown that calls produced from inside burrows are highly sexually attractive (HSA) to females while those produced outside nests are of low sexual attractiveness (LSA). Results showed that most subjects called responsively after the end of WN playbacks but before the onset of conspecific call stimuli although call numbers were similar, indicating that while males adjusted competitive patterns according to the biological significance of signals, their competitive motivation did not change. Furthermore, these data indicate that the frogs had evolved the ability of interval timing. Moreover, when the inter-stimulus interval (ISI) between playbacks was varied, the subjects preferentially competed with HSA calls when the ISI was short (
... The different strategies used by rivals during singing interactions provide eavesdroppers with information on the relative quality or motivation of the interacting males (Naguib 2005). Several studies on birds demonstrate that females use information gathered from singing interactions to direct their sexual behaviours (Otter et al. 1999; Mennill et al. 2002; Leboucher & Pallot 2004; Amy et al. 2008). Other studies demonstrate that males eavesdrop on different singing interactions and that they also use the acquired information in subsequent encounters (e.g. ...
... We can assume that males have the opportunity to hear, and therefore eavesdrop on, male–male singing interactions . Previous studies on domestic canaries have demonstrated that males visually eavesdrop on male– male interactions (Amy & Leboucher 2007) and that females eavesdrop on visual as well as acoustic male– male interactions (Leboucher & Pallot 2004; Amy et al. 2008 ). The domestic canary is thus the only species where both males and females are proven to both visually and acoustically eavesdrop on male–male interactions. ...
Signalling interactions could provide information for an observing third party. This behaviour has been labelled as eavesdropping. Studies on eavesdropping in birds have concerned only few species and have mainly been conducted in the wild. Our experiment was designed to evaluate the effects of eavesdropping on subsequent interactions in male canaries in a controlled laboratory context. The experiment had two stages: a presentation stage and a test stage. During the presentation stage, subjects heard three different interaction types: an alternating interaction, an overlapping interaction or two song sequences presented separately one after the other, i.e. without interaction. Then during the test stage, subjects were allowed to listen to the songs previously heard separately. We noted calls emitted by subjects during the two stages. During the presentation stage, responses of male canaries did not differ according to the type of interaction they could hear. During the test stage, we found a clear effect of the song status on the calls emitted by subjects. They emitted less calls during the songs of the winner than during all other songs. Surprisingly, subjects also produced intermediate responses by emitting fewer calls during the second song previously heard during the presentation phase, and during the song of the looser when compared to the three other songs. Our results show that male canaries obtain information on the relative threat from an overlapping interaction whereas an alternating interaction does not seem to provide any kind of relative information on singers’ status. In following encounters, the higher the potential threat of a singer was, the less the subjects emitted calls, probably to avoid the more serious rival. This inhibiting effect is discussed.
... Naguib & Todt 1997 in nightingales Luscinia megarhynchos ; Peake et al. 2001, 2002 in great tits Parus major; Mennill & Ratcliffe 2004 in black-capped chickadees Poecile atricapillus). Females eavesdrop on overlapping interactions to assess the relative quality of males to determine mate choice (e.g.Leboucher & Pallot 2004 in domestic canaries; Amy et al. 2008) or to direct their extrapair copulatory behavior (e.g. Mennill et al. 2002 in black-capped chickadees). ...
... But such an increase could be costly for the chicks in terms of immunity (Andersson et al. 2004; Mü ller et al. 2005 but see Cucco et al. 2008; Navara et al. 2006; Rubolini et al. 2006) or survival (Sockman & Schwabl 2000). Female canaries have been shown to prefer the overlapping song rather than the overlapped one (Leboucher & Pallot 2004), mostly during the fertile phase of their reproductive cycle (Amy et al. 2008). Therefore, we hypothesized that female canaries should invest more resources in their eggs, in terms V. Garcia-Fernandez et al. ...
Females invest differently in their eggs depending on the quality of their mates. In oscines, female investment is influenced by the quality of male song. In domestic canaries Serinus canaria, as well as in black-capped chickadees Poecile atricapillus, females pay attention not only to the intrinsic quality of male song but can also gather information, by eavesdropping on male–male singing interactions, on the relative quality of males. During these interactions, overlapping the song of the rival is more threatening than alternating. Moreover eavesdropping female canaries have been shown to prefer the overlapping song rather than the overlapped song. The present study was designed to assess the effect of the information gathered by eavesdropping on female investment in eggs. First, we broadcasted overlapping interactions to female canaries. Then, we broadcasted to each female one of the two songs previously heard and collected eggs. Females exposed to overlapping songs laid eggs with greater yolk ratio than females exposed to overlapped songs. In contrast, yolk testosterone quantity and concentration were not affected by the treatment. Moreover, we found a variation between eggs with regard to the testosterone deposited in yolk: both quantity and concentration increased with laying order. Our results suggest that female canaries use information gathered by eavesdropping to differentially allocate resources into the eggs. They suggest that singing interactions could influence chick quality via female investment.
... In some anuran species, the females prefer the leading calls over the following ones, even when they are heterospecific (Legett et al. 2020). Because the precedence effect is an inherent responsive property of the vertebrate auditory nervous system (Zurek 1980(Zurek , 1987Wyttenbach and Hoy 1993;Backwell et al. 1998), and overlap may obscure the delicate temporal components of male calls (Schwartz 1987), females of some species, including birds and frogs, prefer non-overlapped vocalizations (Amy et al. 2008;Martínez-Rivera and Gerhardt 2008). The acoustic environment in the lek or chorus is very complex due to the high levels of background noise such as abiotic noise and Fig. 5 The number of female choices (a) and corresponding latency (b) for each acoustic stimulus within different stimulus pairs. ...
In most anuran species, vocalizations often consist of different notes with various temporal and spectral acoustic attributes which play a crucial role in their survival and reproductive success. Although the first call note might be necessary for anuran communication, we know little about how different notes of the calls influence female choice. The present study used phonotaxis experiments to examine the effects of the notes on female choice in the Anhui tree frog (Rhacophorus zhoukaiyae). The stimulus pair consisted of the original male advertisement call (OC) and one of four revised versions, where the first (WN1), second (WN2), or fifth (WN5) notes were replaced by band-limited white noise (WN), and the second note was replaced by a period of silence (SN2), played back antiphonally. The results showed that (1) the females preferred OC compared with WN1, suggesting the first call note plays an important role in female choice, and (2) the females preferred WN2 and SN2 compared with OC. We discuss the possibility that the second note might be the result of the combined effects of physiological constraint and avoiding backward masking of the second note on the first one over evolutionary time. These results support the notion that the first two functionally antagonistic call notes may influence female choice in this species.
Significance statement
Vocalizations consisting of different components are a prerequisite for acoustic communication. However, the effect of different notes in anuran advertisement calls on female choice is still unknown. We adapted different notes of the original male advertisement call of the Anhui tree frog (R. zhoukaiyae) and played them back to females in order to explore the effects of these modifications on female choice. We found that females preferred male advertisement calls that contained the first note, but not the second one. These results support the idea that the first call note may play an important role in female choice, while the second note might have resulted from the combined effects of physiological constraint and avoiding backward masking of the second note on the first one.
... on the secondary effects of broadcast exposure on the behaviour of fathers. Songbirds of multiple species are known to observe interactions among other birds and use that information to guide their own decisions (Amy et al., 2008;Beecher et al., 2007;Mennill et al., 2003;Suzuki et al., 2014). In our study, adult male swamp sparrows showed more territorial behaviours in response to inland versus coastal song playback (Fig. 5). ...
Animals face many perceptual challenges early in life, including in some cases the need to recognize members of their own species. Early species discrimination abilities are especially well documented for songbirds, with nestlings and even embryos responding preferentially to conspecific vocalizations. It remains unknown, however, whether and how such preferences may be altered by early acoustic experience. In the first field study to intentionally manipulate the sound environment of wild nestlings, we here exposed nestling swamp sparrows, Melospiza georgiana, in the field to playback of song from their own subspecies or from another subspecies that breeds in a different habitat and differs in morphology and song traits. Following an average of 4 days of exposure, we temporarily removed nestlings from their nests and tested them, individually, with unfamiliar consubspecific, heterosubspecific and heterospecific probe songs. We found that nestlings previously exposed to consubspecific songs did not show song type discrimination. By contrast, nestlings previously exposed to heterosubspecific songs chirped more often in response to consubspecific songs as compared to heterosubspecific songs. These results suggest that nestling song discrimination is influenced by auditory experience within their first week of life, that exposure to diverse sets of songs might enhance song discrimination abilities and that perceptual conspecific biases in songbirds are precise to the subspecies level. More broadly, our study implies that events immediately following hatching have the potential to guide later song learning, stimulus categorization and premating isolation among diverging populations.
... Female canaries were exposed to simulated countersinging and then subjected to solo playback of the virtual interactants' songs. The females gave more copulation solicitation displays in response to the overlapping songs than the overlapped songs, but the addition of attractive trill syllables eliminated the effect of song overlapping on female preference (Amy et al., 2008;Leboucher & Pallot, 2004). In a separate experiment, canaries heard simulated countersinging in which one simulated male consistently overlapped the other, and were then exposed to the songs of one of the simulated males (Garcia-Fernandez, Amy, Lacroix, Malacarne, & Leboucher, 2010). ...
Interactive communication occurs when two or more individuals reciprocally exchange signals. It is widespread and common in humans, non-human animals, and even machines. Territorial songbirds participate in a form of interactive communication known as “countersinging.” This chapter reviews research on this model system, with a focus on the last 20 years. It conceptualizes countersinging as a collective behavior that emerges when individuals interact according to rules. I organize research on dyadic countersinging by acoustic domain (time and pattern) and causation (behavioral mechanism, neuro-endocrine mechanism, ontogeny, evolution, and function). Among the topics covered are song overlapping, song rate, variation in song structure, song type switching, soft song, vocal performance, song type matching, countersinging in communication networks, the dawn chorus, and eavesdropping. The chapter ends with a discussion of understudied facets of avian countersinging and recommendations for future research. As the best-studied system of interactive communication in non-human animals, avian countersinging is a valuable model for the evolution of interactive communication.
... But in this thesis, we could not verify that the song preference expressed by female zebra finches was really a sexual preference. Indeed, in opposition to photosensitive species in which it is easy to control the breeding period by modifying light duration in the laboratory and in which the females' sexual receptivity can be easily assessed before the test (e.g. in the canary using Copulation Solicitation Displays, nest-building behaviour or egg-laying; Leboucher et al., 2012;Amy et al., 2008), zebra finches lack seasonality in breeding and are considered as opportunistic breeders (Immelmann, 1962;Zann, 1996). Therefore, it is difficult to assess zebra finch females' sexual receptivity behaviourally before testing, making it impossible to disentangle the effects of sexual preference versus social preference. ...
For a long time, culture has been considered as a human specificity but there is extensive evidence in the animal kingdom that several species exhibit behavioural patterns considered as cultures. Birdsong is a learned behaviour and has been demonstrated as a valid model to study the evolution of vocal culture. The aim of this study is to track the cultural evolution of song in colonies of zebra finches (Taeniopygia guttata), starting with an extreme initial condition under which all male founders produce a very similar song after being trained with the same song model. Two colonies were founded by males singing a same song model and one colony was founded by males singing another song model. Overall, the results show that, in such artificial conditions, the song evolved in a way that the similarity to the initial model was maintained over time and each song model led to different acoustic specificities. This demonstration constitutes the first experimental evidence that song dialects can emerge in the zebra finch, forming distinct vocal cultures. Because such song variations could have biological significance in this social species, we investigated their implications for female preference and social learning. Female zebra finches preferred their native song dialect over a stranger one. Yet, birds of both sexes were not more likely to copy the food choice of a bird singing the dialect of their own colony than the choice of a bird singing a different dialect. This thesis work constitutes one step in understanding the cultural evolution of the zebra finch song in the laboratory and more generally, provides a better understanding of the dynamics of cultural evolution of communication signals, which represent an important topic in language research.
... Although overlapping is considered as an antagonistic signal and used to indicate a willingness to escalate the vocal confrontation (Naguib, 1999), overlap may obscure the fine temporal components and structures of male vocalizations (Schwartz, 1987). Therefore, females of some species including frogs and birds typically prefer non-overlapped signals (Amy et al., 2008;Martínez-Rivera and Gerhardt, 2008). Accordingly, males usually produced non-overlapping calls to avoid the interference of call overlap. ...
Male-male vocal competition is critical for mating success in anuran species; however, it remains unknown that how males regulate their competitive strategies dynamically during competition because calling is highly time-consuming, energetically demanding and likely to increase predation risks. Since different parts of calls will encode different information for vocal communication, we hypothesized that competitive strategies of male frogs may be modulated by the temporal and spectral features of different call notes. To test this hypothesis, the natural advertisement calls (OC), its modified versions with the first call note replaced by white noise (WN) or other notes and with the fifth call note replaced by WN, were played back to the Anhui tree frogs (Rhacophorus zhoukaiyae). Results showed that 1) males produced more competitive calls in response to acoustic stimuli compared to their baseline calling during silence; and 2) males emitted more non-overlapping calls compared to overlapping calls in response to the acoustic stimuli. These results are consistent with the idea that males are flexible to acoustic signals and their competition strategies are modulated dynamically by social contexts.
... Although overlapping is considered as an antagonistic signal and used to indicate a willingness to escalate the vocal confrontation (Naguib, 1999), overlap may obscure the fine temporal components and structures of male vocalizations (Schwartz, 1987). Therefore, females of some species including frogs and birds typically prefer non-overlapped signals (Amy et al., 2008;Martínez-Rivera and Gerhardt, 2008). Accordingly, males usually produced non-overlapping calls to avoid the interference of call overlap. ...
Male-male vocal competition is critical for mating success in anuran species; however, it remains unknown that how males regulate their competitive strategies dynamically during competition because calling is highly time-consuming, energetically demanding and likely to increase predation risks. Since different parts of calls will encode different information for vocal communication, we hypothesized that competitive strategies of male frogs may be modulated by the temporal and spectral features of different call notes. To test this hypothesis, the natural advertisement calls (OC), its modified versions with the first call note replaced by white noise (WN) or other notes and with the fifth call note replaced by WN, were played back to the Anhui tree frogs (Rhacophorus zhoukaiyae). Results showed that 1) males produced more competitive calls in response to acoustic stimuli compared to their baseline calling during silence; and 2) males emitted more non-overlapping calls compared to overlapping calls in response to the acoustic stimuli. These results are consistent with the idea that males are flexible to acoustic signals and their competition strategies are modulated dynamically by social contexts.
... The determination if a male is a high-quality (hotshot) male in passerine species has been consistently correlated to a male's level of aggressiveness, ability to defend his territory from rival males, or to usurp rival males (Dabelsteen and Pedersen 1990;Lampe and Espmark 2003;Kunc et al. 2006). The more aggressive a male is, the more capable he will be at defending his territory from rival males, thus increasing the probability of gaining access to high-quality territories (Lampe and Espmark 2003;Kunc et al. 2006;Amy et al. 2008). Because highly aggressive males typically defend high-quality territories, a highly aggressive male may provide a valuable cue that females can use to gain information about the suitability of the site for building a nest to rear offspring. ...
Emerging research has shown that many species of birds utilize low-amplitude vocalizations (LAVs) in a variety of social interactions; however, the function of these vocalizations in shaping the spatial dynamics of individuals within breeding populations remains unexplored. To gain further understanding of the function of LAVs in this context, I experimentally tested the function of LAVs in the settlement decisions of a migratory songbird (the Veery; Catharus fuscescens) in a manipulated forest soundscape. I manipulated twenty plots through the playback of previously recorded male Veery songs. Half of the plots played back LAVs (i.e., whisper calls) after approximately every five songs while the other half broadcasted only the male song as the control treatment. I located thirty nests during the 4-week experiment (20 in experimental plots, 10 in control). I recorded the GPS location of each nest and monitored each nest until fledging or nest failure. Although nesting in proximity to whisper call plots was marginally non-significant, females settled at whisper call plots more often, earlier in the breeding season, and whisper call plots had a higher probability of being settled more than once. This is the first study to experimentally show how a low-amplitude signal can affect female settlement decisions.
Keywords: low-amplitude vocalizations; settlement decisions; hotshot model; hidden lek; aggressive signals
... Females showed a preference for the overlapping song in the experiment where overlapping or being overlapped was the main difference between males, but not when some males also displayed A-phrases, possibly because the phrases were contradicting male performance in overlapping (Leboucher and Pallot 2004). In another study on the domestic canary, females showed an overall preference for overlapping song and this preference was especially strong on the day before laying the first egg (Amy et al. 2008). Moreover, female domestic canaries hearing overlapping song laid eggs with greater egg yolk ratio than females exposed to overlapped songs, indicating that eavesdropping on male interactions might also influence maternal investment (Garcia-Fernandez et al. 2010). ...
The behavioural decisions animals take directly influence their fitness and thus have a fundamental impact on evolutionary processes. In many animals, acoustic signals play an important role in social decisions with mate choice being among the most apparent ones. Male bird song has played a key role along this line, yet the understanding of how female birds use song to prospect, assess and choose mates in their natural environment is surprisingly limited. A main reason for this limited understanding is that it is very difficult to follow a female during her prospecting and decision process and quantify her experience with different males before she makes a final decision. Here we integrate insights from communication networks, male song traits and female prospecting behaviour to stimulate a more integrative approach on the role of signalling in behavioural and reproductive decisions.
... First, the female preferences could be measured without video and/or sound recordings and, thereby, without analysis of copulation solicitation displays and/ or vocalizations as required in other methods (e.g. Nagle et al., 2002;Drãgãnoiu et al., 2002;Amy et al., 2008Amy et al., , 2015. In addition, Anderson (2009) demonstrated that some females that did not perform CSD did respond in the operant conditioning assay and showed preferences for the same song type than other females. ...
Variation of female preferences is often reported in the literature and could be related to an artefact derived from multiple different methods used. Thus, there is a need to evaluate the influence of different methods when assessing female preferences. The present study aims to compare female preferences obtained from an operant conditioning test and from female vocal responses to male song in the domestic canary (Serinus canaria). In an operant conditioning test, females had the possibility to choose between two keys; a peck on one key elicited a supposed very attractive canary song while a peck on the other key elicited a less attractive song. Meanwhile, female vocal responses were recorded. Our results revealed that female canaries preferred to peck on the key eliciting the attractive song and that they emitted more copulation calls in response to the attractive song compared to the less attractive song. This study shows the congruence of these two methods and further suggests that they are reliable to study female preferences in laboratory conditions.
... produce it accurately (Doupe & Kuhl, 1999), and both males and females must listen to song of conspecifics to make decisions about territorial defense or mate selection (Searcy & Beecher, 2009;Amy et al., 2008). Therefore, songbirds may be used as an unbiased and expert judge of the discriminability of acoustic stimuli, and an ideal comparator to infant listeners. ...
Despite their acoustic similarities, human infants are able to discriminate between infant-directed song (as produced by human adults) and infant-directed speech in both English and Russian. However, experimenters are somewhat limited in what they can test using the preference paradigm with infants. As a complement to a previous infant study (Tsang, Falk, & Hessel, 2016), we asked whether a songbird, the zebra finch, could discriminate infant-directed song and speech in English and Russian, and tested responses to stimuli
that humans could not categorize as either type. Male and female zebra finches learned to discriminate the stimuli in both languages equally well, although females were slightly faster at learning the discrimination, and generalized responses to untrained stimuli of the same categories. Bird responses to stimuli that humans could not categorize likewise did not follow a clear pattern. Our results show that infant-directed song and speech are discriminable as categories by non-humans, that song and speech are as easy to discriminate in both English and Russian, and that comparative studies together can provide more complete answers to research questions about auditory perception than using one species or one language alone.
... The initial experiments along this line were playbacks on nightingales (Luscinia megarhynchos), which reported that territorial males responded more vigorously to the loudspeaker from which the broadcast songs overlapped the songs of the other loudspeaker (Naguib & Todt, 1997) or to the loudspeaker from which leading songs were played, followed by the other loudspeaker without overlap (Naguib, Fichtel, & Todt, 1999). Great tits subsequently have been shown even to combine information from eavesdropping with direct experiences , and female little penguins (Eudyptula minor) (Miyazaki & Waas, 2002), chickadees (Parus atricapillus) (Mennill et al., 2002), and canaries (Serinus canaria) (Amy et al., 2008;Leboucher et al., 2012) appear to use information gained from eavesdropping to guide mating decisions. These and similar studies on eavesdropping in fish have been reviewed in more detail elsewhere (Naguib, 2005;Peake et al., 2005). ...
Animal social networks and animal communication networks are key disciplines for understanding animal social behavior, yet these disciplines remain poorly integrated. In this review, we show how communication and social networks are inherently linked, with social signals reflecting and affecting social networks. Signals carry key information on the quality and direction of social connections and reveal social connections over long distances. Moreover, social signals can directly affect proximity among conspecifics, by facilitating social attraction and repulsion. Social signals thus mediate many of the social networks we observe. Throughout, we discuss a broad range of signal types and interactions, yet with a focus on acoustic signals and show how they reflect and affect social relationships. With this review we aim to inspire further integration of the social network and communication network disciplines, expecting that it will lead to new insights into the dynamics and evolution of animal social behavior.
... Eavesdropping occurs when information is transmitted from one individual (sender) to another (receiver) while one or more eavesdroppers/bystanders that were not addressed pick up the signal [4]. Eavesdroppers can gather reliable information about potential mates by assessing their quality on the basis of behavioral cues, e.g. in fighting [5,6,7] or singing interactions [8,9,10,11]. Eavesdropping females gain information on the relative quality of males at little cost and/or risk [12], as evaluating potential mates might, for instance, expose them to enhanced predation risk [13] or sexual harassment [14]. ...
Animals observing conspecifics during mate choice can gain additional information about potential mates. However, the presence of an observer, if detected by the observed individuals, can influence the nature of the behavior of the observed individuals, called audience effect. In zebra finches (Taeniopygia guttata castanotis), domesticated males show an audience effect during mate choice. However, whether male and female descendants of the wild form show an audience effect during mate choice is unknown. Therefore, we conducted an experiment where male and female focal birds could choose between two distinctive phenotypes of the opposite sex, an artificially adorned stimulus bird with a red feather on the forehead and an unadorned stimulus bird, two times consecutively, once without an audience and once with an audience bird (same sex as test bird). Males showed an audience effect when an audience male was present and spent more time with adorned and less time with unadorned females compared to when there was no audience present. The change in time spent with the respective stimulus females was positively correlated with the time that the audience male spent in front of its cage close to the focal male. Females showed no change in mate choice when an audience female was present, but their motivation to associate with both stimulus males decreased. In a control for mate-choice consistency there was no audience in either test. Here, both focal females and focal males chose consistently without a change in choosing motivation. Our results showed that there is an audience effect on mate choice in zebra finches and that the response to a same-sex audience was sex-specific.
... The acoustic environment of a chorus can be complex because of the spatial distribution of males, intense competition for mates, high levels of background noise, and temporal overlap among calls produced by neighboring males (Wells and Schwartz, 2006). Since call overlap may obscure the fine temporal components of male calls (Schwartz, 1987), females generally prefer non-overlapped signals (Amy et al., 2008;Martínez-Rivera and Gerhardt, 2008). Therefore, with respect to the timing of sex displays, theoretically males should adopt a strategy for minimizing the costs and maximizing the probability of mating success (Byrne, 2008). ...
Male-male vocal competition in anuran species may be influenced by cues related to the temporal sequence
of male calls as well by internal temporal, spectral and spatial ones. Nevertheless, the conditions under which each type of cue is important remain unclear. Since the salience of different cues could be reflected by dynamic properties of male-male competition under certain experimental manipulation, we investigated the effects of repeating playbacks of conspecific calls on male call production in the Emei music frog (Babina daunchina). In Babina, most males produce calls from nest burrows which modify the spectral features of the cues. Females prefer calls produced from inside burrows which are defined as highly sexually attractive (HSA) while those produced outside burrows as low sexual attractiveness (LSA). In this study HSA and LSA calls were broadcasted either antiphonally or stereophonically through spatially separated speakers in which the temporal sequence and/or spatial position of the playbacks was either predictable or random. Results showed that most males consistently avoided producing advertisement calls overlapping the playback stimuli and generally produced calls competitively in advance of the playbacks. Furthermore males preferentially competed with the HSA calls when the sequence was predictable but competed equally with HSA and LSA calls if the sequence was random regardless of the availability of spatial cues, implying that males relied more on available sequence cues than spatial ones to remain competitive.
... role in aggressive interactions between rival males [48,44]. In the case of females, male song is used as an indicator of the singer's quality, reflecting factors such as age and dominance, and is thus used in mate selection (e.g., [1,12]). ...
The two-note fee bee song of the black-capped chickadee ( Poecile atricapillus) is sung at many different absolute frequencies, but the relative frequencies between the start and end of the fee note (the glissando) and between the fee and the bee notes (the inter-note ratio) are preserved regardless of absolute frequency. If these relative frequencies are experimentally manipulated, birds exhibit reduced behavioural responses to playback of altered songs both in field studies and laboratory studies. Interestingly, males appear to be sensitive to alterations in the glissando, while females appear to be sensitive to alterations in both the glissando and the inter-note ratio. In this study, we sought to determine whether the behaviour of male and female chickadees corresponds to differences in zenk protein immunoreactivity (ZENK-ir) in auditory perceptual regions following playback of fee bee songs with typical and altered pitch ratios. Overall, there was a small but significant sex difference in ZENK-ir (females>males), but altering relative frequencies did not reduce ZENK-ir compared to typical song. Birds did vocalize less in response to playback of songs that lacked an inter-note interval, but amount of singing fee bee song, chick-a-dee calls, or gargles was not correlated with ZENK-ir in perceptual regions (caudomedial nidopallium, NCM and caudomedial mesopallium, CMM) or in HVC, which is part of the song system. Our results confirm that ZENK-ir in NCM and CMM is not involved in fine-grain perceptual discrimination, however it did not support the idea that increased vocalizing increases ZENK-ir in HVC.
... The behavioral differences between groups did not reach statistical significance due to the lack of response in some subjects although the percentages of active subjects tended to increase from the WN to the NS to the SS group (0.05<p<0.010). The lack of response in some subjects is probably explained by the fact that female canaries have been found to be more discriminative towards their mate's songs during the last 3 days preceding the laying of the first egg when sexual motivation is high [32]; in this experiment, many females probably did not reach this acme of sexual responsiveness. Therefore these data are in agreement with and tend to confirm the discrimination capacity of these females and also the fact that the number of calls can probably be used as a behavioral index of this discrimination (see [25,33]). ...
In canaries, specific phrases of male song (sexy songs, SS) that are difficult to produce are especially attractive for females. Females exposed to SS produce more copulation displays and deposit more testosterone into their eggs than females exposed to non-sexy songs (NS). Increased expression of the immediate early genes c-Fos or zenk (a.k.a. egr-1) has been observed in the auditory forebrain of female songbirds hearing attractive songs. C-Fos immunoreactive (Fos-ir) cell numbers were quantified here in the brain of female canaries that had been collected 30min after they had been exposed for 60min to the playback of SS or NS or control white noise. Fos-ir cell numbers increased in the caudomedial mesopallium (CMM) and caudomedial nidopallium (NCM) of SS birds as compared to controls. Song playback (pooled SS and NS) also tended to increase average Fos-ir cell numbers in the mediobasal hypothalamus (MBH) but this effect did not reach full statistical significance. At the individual level, Fos expression in CMM was correlated with its expression in NCM and in MBH but also with the frequency of calls that females produced in response to the playbacks. These data thus indicate that male songs of different qualities induce a differential metabolic activation of NCM and CMM. The correlation between activation of auditory regions and of the MBH might reflect the link between auditory stimulation and changes in behavior and reproductive physiology.
Copyright © 2015. Published by Elsevier Inc.
... Many studies found SO to be a stronger threat than song alternating (Amy et al. 2008;Brindley 1991;Dabelsteen et al. 1997;McGregor et al. 1999;Naguib 1999;Naguib et al. 1999;Todt & Naguib 2000;Schmidt et al. 2007); however, this is not the case is some species such as the yellowhammer (Emberiza citrinella) (Osiejuk et al. 2003) and corn bunting (Emberiza calandra) (Osiejuk et al. 2007). ...
Over the last few decades, research into song overlapping produced many – often conflicting – interpretations of its function and culminated in the current debate about the usefulness of this concept. To avoid a deadlock in song overlapping research, we present a new approach to existing evidence and offer several novel hypotheses that might help enhance future experiments. Our analysis offers both a theoretical perspective and specific predictions of each testable hypothesis. We present a detailed analysis of important questions. First, what information does song overlapping convey (is it a signal of aggressive intent or of male quality)? Second, what evolutionary mechanism stabilizes honesty of song overlapping as a signal (is it an index signal, handicap, proximity risk, conventional signal or a modifier)? Additionally, we offer some alternative explanations of the phenomenon (song overlapping as a mask or an incidental phenomenon). We hope to encourage future researchers not only to gather high-quality experimental data, but also to make more careful interpretations, as we believe that no all-encompassing explanation of song overlapping will be formulated any time soon. Focused comparative approaches will be necessary, as song overlapping might have different functions in different species.
... Thus, males could eavesdrop on song contests as an early warning system to gauge the threat posed by potential intruders (Eason and Stamps 1993). Females would also benefit from this ability to assess potential extrapair mates, as they have been shown to make reproductive decisions based on the outcomes of song contests (Mennill et al. 2002(Mennill et al. , 2003Amy et al. 2008;Caro et al. 2010). ...
Animals eavesdrop on dyadic interactions between other individuals to gather information for future mate choice and territory defense decisions. The capacity for eavesdroppers to combine information gathered from overhearing multiple two-way interactions is poorly studied. We tested whether inexperienced (second year) and older (after second year) male black-capped chickadees (Poecile atricapillus) eavesdrop on rivals' song contests to evaluate the relative threat levels of multiple unfamiliar territorial intruders. We used a multiple speaker playback experiment to simulate 3 male territorial intruders (A, B, and C) engaging in 2 successive dyadic song contests, presenting focal males with the information that A was more threatening than B, and B was more threatening than C. We then assayed the response of focal males when presented with simulated intruders A and C without relative information. We predicted that males would defend against the intruder perceived to be the greater threat. Focal males initially responded toward the more threatening intruder (A) significantly more than the less threatening intruder (C), consistent with our predictions. Older birds approached the more threatening intruder (A) significantly more than the less threatening intruder (C), whereas young males showed more variable responses. Our results suggest that male chickadees were able to acquire relative threat information from separate song contests that influenced their responses toward rivals paired in novel contests. These findings indicate that territorial songbirds in communication networks may be capable of integrating information gathered through eavesdropping on multiple interactions.
... A growing volume of research has suggested that signals that are intended for one receiver are readily and frequently received and used by multiple individuals (e.g. canaries: Amy et al. 2008;chickadees: Mennill et al. 2003;katydids: Lang et al. 2005). The individuals that are not directly involved in the signaller-receiver dyad are labelled as audiences or eavesdroppers depending on their role. ...
Abstract The study of communication in a network setting has gained increasing popularity in recent years. While audience effects on aggressive interactions have been studied extensively, male–female interactions have often been overlooked. In addition, little is known about how reproductive status affects the nature of audience effects. Siamese fighting fish, Betta splendens, are a popular subject for communication network studies, but male–female interactions have not been explored in this setting. In this study, pairs of male and female Betta were presented with a male, female or no audience to determine whether the presence of an audience alters the behaviour of the interactants. Within these three audience types, there were four reproductive status conditions with receptivity indicated by nest presence for males and reproductive barring for females. It was predicted that male–female interactions would be affected by the presence of an audience, especially when both interactants are receptive as has been found in male–male interactions in this species. The results suggest that presence of an audience and reproductive status act in combination to influence male–female interactions, but only in interactant-directed behaviours. Not all behaviours were equally affected by these factors. For example, while tail beats to the other interact were greatest when a female audience was present and both the interactants were receptive, this was not true for gill flaring. This study is among the first investigations into audience effects on male–female interactions including the first in Betta and suggests that courtship as well as aggression should be explored in a network setting.
... They, for example, base their mating decisions on it or exhibit other choice related behaviours (e.g. approach behaviour, copulation solicitation displays, differential egg allocation) (Otter et al. 1999;Mennill et al. 2002Mennill et al. , 2003Leboucher and Pallot 2004;Amy et al. 2008;Garcia-Fernandez et al. 2010). Again, all these studies tested female responses to asymmetric, i.e. song overlapping, singing contests between males and confirmed female preferences for the more dominant, i.e. overlapping, male part. ...
In bird communication, listening individuals may obtain information on the quality and motivation of a male not only from solo-singing, but also from song interactions and listeners base their future decisions in territorial and mating contexts on such public information. Eavesdropping on male interactions may thus have a strong influence on sexual selection. In singing interactions, temporal coordination (e.g. overlapping vs. alternating) of two singers as well as structural interaction patterns (e.g. song type matching or repertoire matching) have been described, but the latter is far less studied. By conducting dual-speaker playback experiments with common nightingales Luscinia megarhynchos, we simulated an interaction where one singer was repeatedly song–type matching his counterpart. Playbacks were broadcast to male and female nightingales, and their approach behaviour and singing responses (in the case of male focals) were analysed. We found that both, males and females, spent more time with the matched bird, whereas males additionally sang more songs towards the matching bird. This can be taken as strong hint that eavesdropping occurs in nightingale communication and that listening to male vocal contests might be an important strategy for both sexes to adjust their behavioural output. With regard to the function of song matching, we assume that song-matching is not an aggressive signal per se in nightingales. We rather conclude that vocal leaders within an interaction, here the matched bird, may elicit stronger responses in conspecifics than vocal followers, here the matching bird.
... In the canary, 333 females avoided the winner of a physical contest. Indeed, even if sexual behaviour in 334 canaries is not potentially harmful, females could stay away from winners to avoid a 335 possible re-direction of male aggression (Amy et al. 2008 ...
Maternal effects play an important role in mediating reproductive success; the different allocation of resources in eggs is considered a primary maternal effect. In oviparous vertebrates, there are several substances (hormones, immunoglobulins, antioxidants, antibacterial molecules) that females may allocate differentially. Mate choice is a key factor influencing female reproductive decisions and investment in eggs, but it is not clear to what extent the dominance status of the partner can influence the decision to invest differentially in the quality of eggs. In the grey partridge Perdix perdix, we ranked males for their social status after pairwise dominance tests. Then, females were paired experimentally with dominant or subordinate individuals. We measured testosterone, lysozyme and ovotransferrin concentrations in their eggs. Females paired with dominant males laid eggs with higher testosterone concentration, while egg mass, lysozyme and ovotransferrin concentrations did not differ. With regard to testosterone, because this hormone has been shown to elicit beneficial effects in offspring hatching from grey partridge eggs, our results are in line with the differential allocation hypothesis that females paired with high-quality males should invest more in the current reproductive event.
... While overlapping can occur as a result of chance alone (Searcy & Beecher 2009), many animals vary the timing of signal production either to increase or decrease interference with other signallers (Schwartz 1987;Greenfield 1994a;Gerhardt & Huber 2002;Naguib & Mennill 2010). The strategies animals use to modify interference can vary with species (Schwartz 1987), population (Höbel & Gerhardt 2007), signal modality (Carlson & Copeland 1985;Johnston et al. 1997) and context (Greenfield 1994b;Schwartz et al. 2002), and can have important fitness consequences for the individuals involved (Greenfield 1994a;Mennill et al. 2002;Miyazaki & Waas 2002;Amy et al. 2008;Garcia-Fernandez et al. 2010). ...
Animals that live in communication range of multiple conspecific receivers have the potential to interfere with their neighbours' signals, or to avoid interference by signalling at different times. We used both an observational and experimental approach to study signal timing in lekking tropical birds. We recorded duetting pairs of male long-tailed manakins, Chiroxiphia linearis, during periods when two neighbouring pairs were calling concurrently, and during playback of a simulated pair of nearby rival males. We used three complementary analytical techniques to evaluate whether birds varied the timing of their duet calls relative to nearby animals: circular statistics, resampling analysis and duty cycle models. Our analyses reveal that long-tailed manakins produce duets with nonrandom timing with respect to the calls of their rivals. During natural bouts of concurrent calling, all three analytical techniques revealed that manakins time their duets to avoid overlap. In response to playback, males showed more variable strategies. Males overlapped duets more during playback than they did under natural conditions and, in some cases, they overlapped playback duets at higher levels than would be expected based on chance. Our study shows that males alter the timing of their calls in response to the vocalizations of others around them, and it uncovers similarities in the acoustic signalling behaviour of lekking birds relative to the better-studied signalling behaviour of territorial birds. We also show that different null models of signal timing yield different insights into animal signalling behaviour.
... A network of nocturnally singing males thus even may be considered as a sort of hidden lek in which territorial males display relative to each other (Cockburn et al., 2009;Wagner, 1998) during the time of female prospecting (Roth et al., 2009). Studies on diurnal song in other species support this idea, as laboratory studies on canaries, Serinus canaria, showed that female song preference is affected by the way songs are used in a vocal interactions between males (Amy et al., 2008;Leboucher and Pallot, 2004). Also field studies on great tits (Otter et al., 1999) and black-capped chickadees, Poecile atricapilla, (Mennill et al., 2002) showed that females attend to male-male vocal interactions and subsequently use the obtained information in their mating decisions. ...
In most animals, communication plays a central role in a variety of contexts. In this chapter, we synthesize studies on vocal communication and spatial behavior in nightingales, Luscinia megarhynchos, with other research on songbirds to emphasize the need to integrate studies on communication with spatial and movement data to be able to understand communication in a dynamic social and communication network of individuals. By combing descriptive and experimental studies on singing, along with a communication network approach and studies on spatial behavior of males and females, the chapter takes a more ecological approach to animal communication which should be helpful to better understand the evolution and ecology of animal communication.
... When analyzing the mate choice decisions, we indeed identified a song trait—song bout length—that affected female mate choice decisions (see below for more details). However, females may gain additional information from acoustic male–male interactions (see, e.g., Amy et al. 2008), which were not possible during song recording and are thus not reflected in the song traits measured in this context. When interpreting the results of the mate choice tests, it has to be taken into account that females do not gain a genetic benefit as they did choose between brothers, which has rarely been taken into account in previous studies. ...
The complex songs of songbirds are thought to have evolved through sexual selection. Sexually selected signals must be associated
with costs in order to ensure their honesty as indicator of male quality. Costs may relate to the development of the neural
substrate underlying song learning, which develops already very early in life. Song may, therefore, serve as an indicator
of the early developmental history. This nutritional stress hypothesis has initially been confirmed for a variety of species,
but recent studies using zebra finches as a model species reported somewhat inconsistent effects, and the functional consequences
of changes in adult song phenotype remain unclear. We tested the nutritional stress hypothesis in canaries by manipulating
either the brood size or the food quality postfledging. The brood size manipulation had a significant effect on early development,
and low food quality postfledging led to a transient reduction in body mass. However, we did not find evidence that any of
the song traits measured reflected the early developmental conditions, which is in conflict with the nutritional stress hypothesis.
Canaries may be less vulnerable to nutritional stress or are able to compensate stressful conditions during early development.
However, if males compensated, this compensation may have come at a survival cost. Female mate choice decisions were independent
of the developmental history of a male. Instead, females preferred males singing longer song bouts, a trait that may contain
a heritable component.
KeywordsDevelopmental stress-Sexual selection-Growth-Bird song
... Previous work has shown that female songbirds choose males based on acoustic information; however, that work has shown that these choices are based on circumstances such as males winning singing contests (Amy et al. 2008), producing more song types (Searcy & Marler 1981), maintaining higher energy levels acrossFigure 2. Mean AE SE difference from baseline in movement responses (beak wipes, food visits, pecking bouts, perch hops, ruffles and water visits) of female black-capped chickadees after hearing dominant and subordinate male songs. a number of songs (Forstmeier et al. 2002 ), or producing vocalizations with a higher proportion of elements that are difficult to perform (Ballentine et al. 2004; Podos et al. 2009). ...
In many species, males use auditory signals to attract females and females select males based on their dominance status. Here we show that information on dominance status in male black-capped chickadees, Poecile atricapillus, a small, temperate, North American songbird, can be extracted from individual songs. We found that the relative amplitude of the two notes in the ‘fee bee’ song of this species was more consistent in dominant males. Furthermore, females responded differently to presentations of single song exemplars from males of different dominance status, with females vocalizing more and performing more motor behaviours during the presentation of dominant songs. Our study suggests that non-pitch-based cues within single vocalizations can both reliably indicate relative rank and be discriminated by females.
... However, contrary to our prediction of foraging technique-assortative pair formation through exploitation of the same foraging habitat, both pair formation and nest location were random with regards to foraging specialisation. As our main research question was whether foraging technique would affect partner choice and pair formation, we did not measure several other variables known to affect female preferences and pair formation, such as competitive interactions between males over food [70], intrasexual competition for mates [71], [72], the mate choices of other females ([73] and references therein), or male song complexity and performance [66]. A previous study showed that female zebra finches from experimentally reduced (2–3 chicks) or enlarged (5–6 chicks) broods preferred the songs of males from broods with the same brood size as their own [40]. ...
Successful foraging is essential for survival and reproductive success. In many bird species, foraging is a learned behaviour. To cope with environmental change and survive periods in which regular foods are scarce, the ability to solve novel foraging problems by learning new foraging techniques can be crucial. Although females have been shown to prefer more efficient foragers, the effect of males' foraging techniques on female mate choice has never been studied. We tested whether females would prefer males showing the same learned foraging technique as they had been exposed to as juveniles, or whether females would prefer males that showed a complementary foraging technique.
We first trained juvenile male and female zebra finches (Taeniopygia guttata) to obtain a significant proportion of their food by one of two foraging techniques. We then tested whether females showed a preference for males with the same or the alternative technique. We found that neither a male's foraging technique nor his foraging performance affected the time females spent in his proximity in the mate-choice apparatus. We then released flocks of these finches into an aviary to investigate whether assortative pairing would be facilitated by birds taught the same technique exploiting the same habitat. Zebra finches trained as juveniles in a specific foraging technique maintained their foraging specialisation in the aviary as adults. However, pair formation and nest location were random with regard to foraging technique.
Our findings show that zebra finches can be successfully trained to be foraging specialists. However, the robust negative results of the conditions tested here suggest that learned foraging specializations do not affect mate choice or pair formation in our experimental context.
... Moreover, interactions between two individuals can be 47 meaningful to other conspecifics (McGregor & Dabelsteen 1996). For example, in male songbirds, singing 48 interactions influence the social ranks of the competitors and the choice of the eavesdropping females (Amy et 49 al. 2008; Mennill et al. 2003; Naguib 2005). 50 In this paper, we propose a new experimental framework that overcomes the limitations induced by 51 human intervention by introducing a closed-loop automatic interaction, based on fully automated sound analysis 52 and playback techniques. ...
In the field of songbird research, many studies have shown the role of male songs in territorial defense and courtship. Calling, another important acoustic communication signal, has received much less attention, however, because calls are assumed to contain less information about the emitter than songs do. Birdcall repertoire is diverse, and the role of calls has been found to be significant in the area of social interaction, for example, in pair, family, and group cohesion. However, standard methods for studying calls do not allow precise and systematic study of their role in communication. We propose herein a new method to study bird vocal interaction. A closed-loop computer system interacts with canaries, Serinus canaria, by (1) automatically classifying two basic types of canary vocalization, single versus repeated calls, as they are produced by the subject, and (2) responding with a preprogrammed call type recorded from another bird. This computerized animal-machine interaction requires no human interference. We show first that the birds do engage in sustained interactions with the system, by studying the rate of single and repeated calls for various programmed protocols. We then show that female canaries differentially use single and repeated calls. First, they produce significantly more single than repeated calls, and second, the rate of single calls is associated with the context in which they interact, whereas repeated calls are context independent. This experiment is the first illustration of how closed-loop bird-computer interaction can be used productively to study social relationships.
... Parameters. Visual system modeling has become an increasingly pervasive feature of studies on the evolution of male coloration in vertebrates (e.g., Hudon et al. 2003;Loyau et al. 2007;Amy et al. 2008;Delhey and Peters 2008;Stoddard and Prum 2008;Lenouvel et al. 2009), replacing the use of computationally simpler parameters derived from raw spectra. However, visual system models are simplifications of visual processing phenomena (Lee 2008) and may themselves introduce undesirable artifacts into data analyses. ...
Color ornaments are often viewed as products of countervailing sexual and natural selection, because more colorful, more attractive individuals may also be more conspicuous to predators. However, while evidence for such countervailing selection exists for vertebrate color ornaments (e.g., Trinidadian guppies), similar studies have yet to be reported in invertebrates. Indeed, evidence for female mate choice based on extant variation in male coloration is limited in invertebrates, and researchers have not explicitly asked whether more attractive males are also more conspicuous to predators. Here we provide evidence that more chromatic male cabbage white butterflies (Pieris rapae) are more attractive to females but should also be more conspicuous to predators. Female P. rapae preferentially mate with more chromatic males when choosing from populations of males with naturally occurring or commensurate, experimentally induced color variation. Mathematical models of female color vision confirm that females should be able to discriminate color differences between prospective mates. Further, chromatic and luminance contrast scores from female visual system models better predicted male mating success than did measures of male color derived more directly from color spectra. Last, models of avian color vision suggest that preferred males should be more conspicuous to known avian predators.
THE BIRDS OF SAUDI ARABIA are extraordinary. In total, 499 species have been recorded in the Kingdom. This incredible diversity includes some of the most beautiful birds on earth, some of the most fascinating, some of the most bizarre, some of the most migratory, some of the rarest, some of the smallest, some of the largest, and some of the fastest birds on earth. Indeed, the birds of Saudi Arabia should be world famous.
Eavesdropping on interactions between conspecific animals provides a low‐cost method for assessing other individuals. Asymmetries in territorial counter‐singing interactions in songbirds provide a rich source of information for eavesdroppers about differences between the singers. Yet, little is known about the relationship between interactive singing in a natural, low‐arousal context among territorial neighbours and individual traits of males. We used a microphone array to monitor natural counter‐singing interactions in great tits ( Parus major ) during nest building, at the onset of the breeding season. We quantified song overlapping and song matching for 30 pairs (dyads) of interacting males, singing at their nest, respectively. We then compared these behaviours to five traits for 28 males: body condition, plumage ornamentation, offspring provisioning behaviour, offspring weight and breeding site quality. We found no relationship between a male song overlapping or matching behaviour and any of the measured traits. Therefore, our results do not support the idea that short‐term asymmetries in low‐arousal long‐range singing interactions among neighbours reflect differences in these fitness‐related traits. Instead, our findings suggest that such singing asymmetries have less signal value in the absence of an immediate conflict but instead reflect short‐term motivational differences, as shown in previous investigations.
Animals need to adapt their motor production to challenging social conditions at behaviorally-relevant time scales. Here, we use telemetric recording technology from freely-behaving canaries in natural-like social conditions in which male canaries compete for females. We report that male canaries influence each other's singing during 'duels' characterized by temporal overlaps of their songs, which are often followed by physical aggression. Duels evolve in time and both canaries can lead or follow the other canary's song on a song-to-song basis. Remarkably, overlapping behavior induces singing plasticity: both song length and its variability increase when canaries overlap their songs. Furthermore, song acoustic properties reveal a link between dueling and song similarity. Altogether, results show that canary singing behavior is plastic in social environments.
Mate choice is the result of intra‐ and intersexual selection. Even though a consensus between females is often observed in favour of some males, different constraints can affect their choice. Context (early learning, mate‐choice copying, prior experience, etc) and/or condition (genetics, body condition, age, etc) can deflect the choice of a female from its ‘standard of beauty’. In domestic canaries Serinus canaria, females display their acceptance of a male by producing a particular sexual behaviour called ‘copulation solicitation display’ (CSD). Previous studies have shown that the number and intensity of these CSDs are more important when females listen to sexy ‘A’ phrases with a rapid tempo (A16) in comparison with A phrases with a slow tempo (A8). In this study, we assess the relationship between food quality (highly or poorly diversified food during a short period) and female choosiness towards these two types of phrases. We confirm that females discriminate between A16 and A8. Nevertheless, the difference between the number of sexual responses towards A16 and A8 is weaker among females with a poorly diversified food diet in comparison with females with a highly diversified food diet. This suggests that even a short‐term modification of condition could decrease females’ selectivity towards high‐value stimuli and increase their response rates towards low‐value signals.
Any signal must get from a sender to a receiver if information is to be transmitted. In the case of bird song, the acoustic properties of the habitat may hinder this being achieved. However, birds as senders and receivers have evolved numerous adaptations to overcome the problem of getting the message across. In this chapter, we explore habitat-dependent patterns of sound transmission, the effects of noise, signal perception, and signal interpretation such as auditory distance assessment with a specific focus on the solutions that selection has generated. We argue that along with other possible selective forces, such as sexual selection, the combination of environmental constraints on signal transmission, noise levels, and the use of signal degradation as a distance cue need mutual consideration to gain a more thorough understanding of the astounding variety of avian song and the many different ways in which birds use it.
In a series of four experiments, we examined the relationship between male dominance and female preference in Japanese quail, Coturnix japonica. Female quail that had watched an aggressive interaction between a pair of males preferred the loser of an encounter to its winner. This superficially perverse female preference for losers may be explained by the strong correlation between the success of a male in aggressive interactions with other males and the frequency with which he engages in courtship behaviours that appear potentially injurious to females. By choosing to affiliate with less dominant male quail, female quail may lose direct and indirect benefits that would accrue from pairing with dominant males. However, they also avoid the cost of interacting with potentially harmful, more aggressive males. © 2003 Published by Elsevier Ltd on behalf of The Association for the Study of Animal Behaviour.
Introduction, Interactions between individuals make up a significant part of life in social animals. They form a crucial behavioural mechanism establishing and maintaining particular spacing patterns among individuals and groups of individuals and are inherent in the regulation of social relations. Animals interact with each other in a broad range of contexts, such as during intersexual competition, mate choice, or parent–offspring communication, but still many of the underlying principles share common ground (Hauser, 1996; Bradbury & Vehrencamp, 1998). It is well documented that the performance of individuals in interactions has profound implications for the resolution of conflicts over resources, such as mates, food or space. Interactions may consist of complex behavioural displays or may be based exclusively on signals in either one or several signalling modalities. Vocal interactions are among the most conspicuous forms of interactions and have been well studied in several taxonomic groups, such as insects, anurans and birds (Bradbury & Vehrencamp, 1998). In birds, vocal interactions are most evident in parent-offspring communication (Kilner & Johnstone, 1997; Ch. 9), calling and singing in group-living species (Farabaugh & Dooling, 1996; Zann, 1996), duetting in tropical songbirds (von Helversen, 1980; Farabaugh, 1982) and in singing interactions between male territorial songbirds (Todt & Naguib, 2000). In this review, I will focus on singing interactions in male territorial songbirds. Their vocal interactions are among the most striking examples of bird vocal communication and are an established model for studies on territoriality and communication networks (McGregor, 1993; McGregor & Dabelsteen, 1996; Todt & Naguib, 2000).
The evolution of signals has mainly been considered in the context of an emitter-receiver dyadic interaction. However, communication usually occurs in the presence of individuals (an audience) that are not directly involved in the communication interaction, and it is more realistic to assume that signal evolution occurs in a network. Several types of information could be available to an audience, and, therefore, the presence of an audience could have effects on the behavior of the communicating animals and on signal evolution. We investigated whether the presence of an audience of conspecifics affected intrasexual aggressive communication in male fighting fish. We found that if the audience was a female, males increased the intensity of conspicuous displays that can be used in communication with both males and females and decreased highly aggressive displays that are solely directed to males. If the audience was a male of similar size, there was no significant change in the way in which males displayed. These results suggest that the presence of an audience could be one reason that many long-range and conspicuous signals are often shaped to transmit information to both males and females.
Song overlapping in birds is used and perceived as a signal of aggression, and evidence suggests that eavesdropping females base their extrapair mating decisions on the performance of males in vocal contests. In our study population of nightingales a large proportion of territorial males remain unpaired throughout the breeding season. A comparison between subsequently mated males and unpaired males may reveal whether females could use singing performance during vocal interactions in their choice of a social mate. We investigated how males that differed in their subsequent pairing status overlapped a noninteractive playback during the period of mate attraction, and how males used specific structural song components in response to playback. Subsequently mated males overlapped more playback songs than did males that remained unpaired throughout the breeding season. Males also adjusted the use of specific song components and decreased song rate during playback, suggesting that the flexible use of structural song components is more important in vocal contests than increasing song output. Because song overlapping is thought to be a signal of aggression, more aggressive males seem to have greater pairing success.
Birdsong is a sexually selected trait that serves in territory defence and mate choice. Individual song traits can be affected by the body condition of the male and thus may reflect his quality. Such relations between male quality and general singing performance raise the question whether differences in male quality also affect response strategies used in dyadic interactions. To address this question, we studied the relation between pairing success of male common nightingales, Luscinia megarhynchos, and their responses to rivals posing different levels of threat. Using interactive playback, we exposed males prior to mating to either aggressively or moderately singing rivals (by song overlapping and song alternating, respectively). Males that remained unpaired throughout the season (bachelors) interrupted their singing significantly more often after being overlapped than after alternating playback, whereas subsequently mated males kept the number of singing interruptions more constant across playback treatment. This suggests that subsequently paired males are less discriminative than are bachelors when challenged by rivals varying in aggressiveness. Regardless of playback treatment, males that later became paired responded significantly more strongly than did bachelor males. Thus, an increase in singing after a vocal interaction prior to mating predicted future mating success.
The domesticated canary (Serinus canaria) is one of the most widely used songbird species to study (1) neural mechanisms of behavioural plasticity and (2) mechanisms of song based female mate choice. Despite numerous studies of the singing and seasonal changes in the song of these animals under laboratory conditions, the present paper describes the results of the first systematic study of the song of the non-domesticated, free-living relatives of the domesticated canary, the island canary (Serinus canaria). The songs of ringed males of the canary population Ilhéu Chão (Madeira) were studied at different times of the year including the spring breeding and autumnal non-breeding season. In the breeding season songs are on average longer and the repetition rate of syllables is higher compared to the non-breeding season. The syllable repertoire size does not change seasonally. Longitudinal studies of individual males confirm these results of the population average. Further, this approach showed that the repertoire composition of individual males changes seasonally with a significant increase of fast-frequency modulated syllables and a decrease of whistle-type syllables during the breeding season. Playback experiments showed that the fastfrequency modulated syllables of the male island canaries are sexually attractive, if used in standard courtship solicitation tests with female canaries under laboratory conditions. This suggests that seasonal changes in the song temporal pattern are a general feature of canaries, domesticated or not while seasonal changes in repertoire composition is an adaptive feature of island canaries, most likely lost during domestication.
Recent studies have pointed out that passerine females pay great attention to male territorial interactions and that they extract information on the quality of males from their territorial songs. We investigated whether female domestic canaries use information gained through eavesdropping when they choose mates. We evaluated the females' sexual preferences for tape-recorded male songs previously heard during an ‘interaction-like’ situation during which the song of one male overlapped the song of the other. Females were tested during two consecutive experiments. In the first experiment, we measured the preference for male songs containing sexually attractive phrases; in the second, the attractive phrases were removed. When a sexually attractive phrase was included in the song, the females failed to show a significant preference but in the second experiment, the females preferred the songs of males that appeared to be able to overlap the songs of their opponents. In the first experiment, the information might have been contradictory: on the one hand, some males seemed to be of poorer quality than others, as they were losing the song contest, but, on the other hand, these same males were producing songs with a sexually attractive phrase, regarded as a signal of quality; the females might have been confused by this apparently inconsistent information. Overall, this study agrees with previous work on eavesdropping, and extends the evidence for such eavesdropping as a choosy female sexual strategy across species.
Fundamental frequency (F 0) is the vocal acoustic parameter closest to what we perceive as pitch. Men speak at a lower F 0 than do women, even controlling for body size. Although the developmental and anatomical reasons for this sex difference are known, the evolutionary reasons are not. By examining fertility-related variation in women's preferences for men's voices, the present study tests the hypothesis that female choice for good genes influenced the evolution of male voice pitch (VP). Unlike previous correlational studies that did not consider the effects of menstrual phase and mating context on women's preferences for male VP, the present study includes these variables and utilizes experimental pitch (P) manipulations. Results indicate that low VP is preferred mainly in short-term mating contexts rather than in long-term, committed ones, and this mating context effect is greatest when women are in the fertile phase of their ovulatory cycles. Moreover, lower male F 0 correlated with higher self-reported mating success. These findings are consistent with the hypothesis that an association between low male VP and heritable fitness led to the evolution of the observed patterns in women's P preferences and men's mating success and that these patterns influenced the evolution of low VP in men. However, alternative explanations are considered.
Secondary sexual characters in many species function both in male-male competition and as cues for female choice. Based on a literature compilation of existing knowledge of traits with this dual function, we propose that they commonly arise through intrasexual selection processes and serve as honest signals to other males regarding fighting ability or dominance. Faking these traits, here called armaments, (i.e. weapons and status badges) is difficult, as they are constantly put to trial in male-male contests. Females that subsequently utilize them as indicators of male phenotypic quality when selecting a partner will benefit by acquiring males of higher quality to father their offspring. Thus, evolution of armaments through male-male competition is seen as a usually initiating process, whereas female choice later may assume a role as an additional selective factor. The reverse, that males use information from traits evolved through female choice, is, however, also possible. The traditional view of independently evolved and temporarily unordered intra-and intersexual selection processes fails to explain dual trait functions. Moreover, our model may more satisfyingly than traditional ones explain how trait honesty and trait genetic variance are maintained: theoretical and empirical evidence suggests that such honesty and variation are more easily maintained under male-male competition than under female choice.
The scientific value of the outcome of an experiment is closely related to its design and analysis. This article deals with
the design issues of pseudoreplication (whether the experimental design has the statistical features needed to answer the
question as posed) and execution errors (problems arising from how the experiment was conducted). Three issues of analysis
are also dealt with: the number and type of response measures to record; how measures should, and should not, be combined
into a single response measure; and how to interpret an apparent lack of response. Interactive playback is considered separately
because it raises its own specific design and analysis issues. Although the examples generally refer to video playback, these
issues are common to all experiments in behaviour.
Interactive playback experiments were used to study the signal value of alternating and overlapping singing in the Yellowhammer Emberiza citrinella. We carried out interactive playback experiments in which 13 males were subjects of two treatments that differed in temporal pattern of playback song delivery (alternating vs overlapping). We measured 12 parameters of males' response, belonging to three categories: song output, call output and mobility (distance from loudspeaker and flights). The results do not confirm the hypothesis that the overlapping pattern is a signal of stronger threat, as compared to the alternating pattern. Overlapping and alternating playbacks generally elicited a similar response, characteristic for highly aroused males. The only significant difference found concerned latency of approach to the loudspeaker during the playback stage. When playback alternated with songs of males, the birds gained higher scores on the axis of that response measure. Such a result was linked to differences in how the alternating and overlapping playbacks affect detection and localisation of simulated rivals, rather than to the signal's threat value itself. The strong response of Yellowhammer males is consistent with the high intrusion rate and possibility of extra-pair copulation in this species, which probably simplifies close-range communication towards more aggressive and unequivocal repelling of rivals irrespective of the temporal patterning of song.
Interactive playback experiments were used to study the signal value to the corn bunting, Miliaria calandra, of alternating and overlapping singing. We subjected 15 males to two stimuli that differed in the temporal pattern of song
playback (alternating or overlapping). We measured eight characteristics of the males’ response in two categories—song output
and movements. Overlapping and alternating playback elicited a similar song response, characteristic of highly aroused males.
Song response correlated positively with males’ singing activity before playback, irrespective of stimulus. There were significant
differences between latency of approach to the loudspeaker and number of flights. Birds approached the loudspeaker more quickly
and spent more time close to it when playback alternated with their songs. The results suggest overlapping song could be interpreted
as a stronger threat but elicits a more cautious, rather than stronger, response than the alternating pattern. Males were
found to shorten songs during the playback compared with songs sung before and after stimulation. The only predictor of degree
of song shortening was song activity before the playback began. It should, therefore, be regarded as a signal which is related
to escalated, close-distance counter-singing.
In a wide range of animal species, males coerce females to mate with them, either by physically forcing them to mate, by harassing them until they mate or by punishing persistent refusal to mate. The first section of this paper argues that the possibility of forced copulation can generate arms races between males and females that may have substantial costs to both sexes. In the second section, it is suggested that sexual harassment commonly represents a ‘war of attrition’ between the sexes; existing game theory models that may apply to sexual conflict over mating decisions are reviewed. The third section develops a simple prospective model for the evolution of intimidation by punishment in situations where males can raise the probability that females will accept their advances in future by punishing them for refusal to mate. Where the benefits of sexual coercion to males are high, all three male strategies may develop to a point where they have substantial costs to females. In the final section, evidence that female behaviour is adapted to minimizing these costs is reviewed.
The function of bird song is closely linked to sexual selection. A fundamental question regarding the evolution of sexually selected male signals is how their honesty is maintained. The neural space required for storing a large song repertoire size has traditionally been identified as a key constraint. However, it is often forgotten that bird song is a multifaceted behaviour, and that the different characters that comprise it have specific costs. Recent research has revealed the existence of new constraints, such as social aggression or learning opportunities, which limit the expression of several song characteristics. We review the existing evidence for each of these constraints, revealing some major gaps in our knowledge of this fascinating biological system.Bird song is a multifaceted behaviour comprising of different characteristics that have specific costs. New constraints are highlighted that limit the expression of several of these characteristics
The mate choices of sexually experienced, female Japanese quail, Coturnix japonica, are influenced by information acquired by observation of potential partners engaging in social interactions. Female quail show an increased preference both for males that they have seen mate with another female and for the less aggressive of a pair of males that they have watched interact aggressively. We examined effects of females' prior sexual experience on their use of such public information when choosing a partner. We found that virgin female quail, like female quail with sexual experience, increased their preference for a male after seeing him mate with another female. Whereas sexually experienced females preferred the less aggressive member of a pair of males that they had seen engage in an agonistic encounter, virgin female quail preferred the more aggressive member of such a pair. We interpret the results as indicating that sexual experience plays little role in the development of mate-choice copying by female quail, whereas experience of punishing aspects of interactions with conspecific males reverses naïve female quails' positive response to relatively aggressive members of the opposite sex.
In a series of four experiments, we examined the relationship between male dominance and female preference in Japanese quail, Coturnix japonica. Female quail that had watched an aggressive interaction between a pair of males preferred the loser of an encounter to its winner. This superficially perverse female preference for losers may be explained by the strong correlation between the success of a male in aggressive interactions with other males and the frequency with which he engages in courtship behaviours that appear potentially injurious to females. By choosing to affiliate with less dominant male quail, female quail may lose direct and indirect benefits that would accrue from pairing with dominant males. However, they also avoid the cost of interacting with potentially harmful, more aggressive males.
Inferences about mechanisms at one particular stage of a visual pathway may be made from psychophysical thresholds only if the noise at the stage in question dominates that in the others. Spectral sensitivities, measured under bright conditions, for di-, tri-, and tetrachromatic eyes from a range of animals can be modelled by assuming that thresholds are set by colour opponency mechanisms whose performance is limited by photoreceptor noise, the achromatic signal being disregarded. Noise in the opponency channels themselves is therefore not statistically independent, and it is not possible to infer anything more about the channels from psychophysical thresholds. As well as giving insight into mechanisms of vision, the model predicts the performance of colour vision in animals where physiological and anatomical data on the eye are available, but there are no direct measurements of perceptual thresholds. The model, therefore, is widely applicable to comparative studies of eye design and visual ecology.
The costs to females of participating in extrapair copulations is an interesting but hitherto neglected topic in behavioral ecology. An obvious potential cost to females is male physical sanctions. However, although retaliation and punishment by male partners has been proposed as a basic cost for female extrapair behavior in theory, it has not been experimentally demonstrated. We studied the breeding biology of the lesser gray shrike (Lanius minor) and combined field observations and a field experiment to show that (1) there is a high intrusion rate during the female's fertile period, and extrapair copulations occur in this population; (2) by detaining females during the fertile phase, males were induced to retaliate physically against their partners, thereby increasing costs related to female extrapair behavior; and (3) there were no obvious costs to males of punishing their mates. DNA fingerprinting reveals that extrapair paternity is rare or absent in this population. Although we cannot conclude that monogamy at the genetic level is the result of male retaliation, we do show that male physical sanction is a cost that deceptive females have to assume. Males' strategies based on coercion should be considered when explaining variation in extrapair paternity across species. Copyright 2003.
FEMALE choice of mates based on the expression of characters that correlate with male quality remains a controversial and largely untested idea 1. By choosing quality males, females stand to gain resources 2, genetic benefits for their offspring 3-5, or both. In the house finch (Carpodacus mexicanus), male plumage coloration is a function of dietary intake of carotenoids 6,7. Here I present results of field studies that indicate that females prefer to mate with colourful males and that plumage brightness correlates with a male's capacity for parental care and perhaps its genotypic quality. Artificially brightened males paired more quickly and frequently than sham control or lightened males. Among unmanipulated males, plumage coloration was correlated with nest attentiveness and overwinter survival. In addition, there was a positive correlation between the coloration of fathers and sons. Peer Reviewed http://deepblue.lib.umich.edu/bitstream/2027.42/62564/1/350337a0.pdf
Male singing behaviour correlates with extra-pair success in several passerine birds. Singing interactions during territorial contests provide relative information on the males involved. Such information may be important in female extra-pair behaviour and eavesdropping on singing interactions among males may allow females to make such relative assessments. We used interactive playback to instigate singing contests with male great tits during the peak fertile period of their mate in an attempt to alter females' assessment of mates' quality relative to neighbours (potential extra-pair partners). We escalated a contest to one male (by overlapping his songs) and then subsequently de-escalated a contest (by alternating) to a neighbour. Intrusions onto neighbouring territories by females mated to either treatment male were then monitored. Females mated to escalation treatment males were more likely to intrude following playbacks than females mated to de-escalation treatment males. Although the absolute song output of males did not differ between treatments, males produced more song relative to playback in de-escalation treatments and relative song output was positively correlated with female intrusions. Therefore, female great tits eavesdrop on singing interactions and change their visitation rates to neighbouring territories according to their mate's singing performance relative to neighbours.
Microspectrophotometric measurements of retinal photoreceptors from the European starling (Sturnus vulgaris) revealed four classes of single cone, containing visual pigments with wavelengths of maximum absorbance ( max) at 563, 504, 449 and close to 362 nm. The two longer-wave-sensitive single cones contained brightly coloured oil droplets which cut off light below 572 and 514 nm, respectively. The 449 nm max pigment was associated with a 'colourless' oil droplet with peak measured absorptance below 400 nm. The ultraviolet-sensitive visual pigment was paired with a transparent oil droplet which showed no significant absorption above 350 nm. A single class of double cone was identified, both members of which contained the longwave-sensitive ( max 563 nm) visual pigment. The principal member of the double cone contained an oil droplet with a topographically variable cut-off wavelength below 471 nm; the oil droplet found in the accessory member was only measured in the ventral retina and displayed three distinct peaks of absorption at approximately 430, 450 and 480 nm. Rod photoreceptors had a max at 503 nm. A new polynomial for fitting visual pigment templates to ultraviolet-sensitive visual pigment data is given. Topographic density measurements of the different cone classes were made using Nitroblue-tetrazolium chloride to label selectively bleached photoreceptors. The two classes of shortwave-sensitive single cone were more abundant in the dorsal retina, and longwave-sensitive single cones were notably less abundant in the dorso-temporal region of the retina, which subserves binocular vision.
Inferences about mechanisms at one particular stage of a visual pathway may be made from psychophysical thresholds only if the noise at the stage in question dominates that in the others. Spectral sensitivities, measured under bright conditions, for di-, tri-, and tetrachromatic eyes from a range of animals can be modelled by assuming that thresholds are set by colour opponency mechanisms whose performance is limited by photoreceptor noise, the achromatic signal being disregarded, Noise in the opponency channels themselves is therefore not statistically independent, and it is not possible to infer anything more about the channels from psychophysical thresholds. As well as giving insight into mechanisms of vision, the model predicts the performance of colour vision in animals where physiological and anatomical data on the eye are available, but there are no direct measurements of perceptual thresholds. The model, therefore, is widely applicable to comparative studies of eye design and visual ecology.
Introduction All communication occurs in a network environment with the exception of a subset of systems that unequivocally meet both of the following criteria: (a) a signal can never be received by more than one receiver; (b) a receiver can never receive more than one signal simultaneously. In other words, all communication networks have at least one of two defining properties: (a) signals can be, at least potentially, received by several receivers; and (b) receivers can, at least potentially, receive signals from several signallers at any one time. Consequently, in moving from a dyadic consideration of communication to a network view, signallers and receivers both take on a range of costs and benefits, which are the theme of this book. In this chapter, I will consider the implications of a particular type of receiving behaviour that becomes possible in a network, namely eavesdropping. I will begin by reviewing different definitions of eavesdropping that are found in the literature and the evidence for different types of eavesdropping, distinguishing between eavesdropping on signals and eavesdropping on signal interactions. I will then examine the costs, benefits and implications of eavesdropping on interactions, as recognition of this phenomenon emerged from considerations of qualitative differences between dyadic and network views of communication (McGregor, 1993; McGregor & Dabelsteen, 1996).
Introduction, Asymmetry in parental investment often predicts that females should be choosier about prospective mates than males. It is commonly assumed that females assess male characteristics during mate choice, but which traits are assessed, and how they influence female decision making, is not well understood. Current models of mate choice suggest females may sequentially sample a pool of males, memorizing levels of trait expression among comparison males, or else accept the first male that exceeds some minimum threshold value of mate quality. Recent tests of communication network theory suggest that these models may have to be revised because females can tap into advertising signals broadcast in a network fashion. Such behaviour could reduce costs of mate searching, as signals are perceived simultaneously, allowing instantaneous relative comparisons. In this chapter, we explore the potential of females to extract comparative information on the relative quality of males for use in reproductive decision making. We focus primarily on primary mate choice decisions (i.e. initial selection of a mating partner) and secondary mate choice decisions (i.e. mating decisions that arise after social pairing, which may include extra-pair copulations or ‘divorce’ of the current mate to pair with another male) based on acoustic signals in territorial passerines; however, the ideas that we present should be applicable to other taxa and other sensory modalities. Finally, we discuss the potential impacts of habitat alteration on females' abilities to use network assessments for mate choice.
The song of male canaries (Serinus canaria) differs greatly from one strain to another (wild and different domesticated breeds) depending on breeders' attempt during selective breedings. Female canaries (common canary strain) previously treated with estradiol were tested for their sexual copulation solicitation display in response to heterospecific and conspecific song stimuli. Heterospecific songs, winter wren (Troglodytes troglodytes) and greenfinch (Chloris chloris), elicited significantly weak reactions from females, but most of the females did react to these heterospecific songs. Two conspecific songs, the females' own strain song and a Border song, elicited significantly strong reactions compared to Harzer roller. A wild canary song has an intermediate song potential between Border and Harzer roller. As a whole these results support the ideas that artificial selection may have relaxed the strength of reproductive isolation and sexual selection.
Male Marsh Wrens (Cistothorus palustris) sing with immediate variety (i.e. AB CDE . . .); they progress rapidly through their song repertoires and tend to countersing with the same song types. Intensive study of two hand-reared males in the laboratory now confirms that both the song types and the song sequences are learned. Furthermore, the leader/follower roles during countersinging duels are not determined at random. In this study, Bird 1 dominated Bird 2 in physical encounters; Bird 2 often followed (i.e. matched) the song type just sung by Bird 1, but Bird 1 matched the songs of Bird 2 only when the songs of the latter were electronically amplified. The leader/follower roles in countersinging may be ritualized expressions of dominance and subordinance, respectively, and could reveal to both males and females the relative vigor of IMITATION plays an important role in the ontogeny of song in many songbird species (e.g. Nottebohm 1972, Kroodsma 1977), and if juveniles either remain at or return to the locality where songs were learned, interacting breeding males will possess similar songs. If a male has only one song type in his repertoire, temporal adjustments in song delivery may be used to achieve interference or avoidance (Wasserman 1977), but when males imitate several songs and develop sizeable rep- ertoires of different song types, the potential for complexity of interactions during countersinging is escalated. Studies of Chaffinches (Fringilla coelebs), Great Tits (Parus major), Black-crested Titmice (Parus bicolor), Cardinals (Cardinalis cardi- nalis), Rufous-sided Towhees (Pipilo erythrophthalmus), etc., have revealed that neighboring males often respond to one another or to a tape recording (of a song from the local "dialect") with matching song types (Hinde 1958, Gompertz 1961, Lemon 1968a, b, Kroodsma 1971, respectively; see Falls and Krebs 1975 for an
The study of threat displays has long been an area in which theory and empirical work have each spurred the other forward. Communication is currently the focus of great interest and effort on the part of modellers. A great deal that classical ethologists have accurately described about threat displays still lacks adequate explanation. Here we review the empirical literature on the use of threat displays by birds competing for small valued resources, both to refocus theoretical attention upon the key characteristics of threat and to assess the degree to which current theory explains these characteristics. We aim to demonstrate that threat displays communicate information about aggressive motivation, but are not handicaps. Handicap models predict a single graded display, while the vast majority of studies report repertoires of about four to six discrete threats for any given species. These displays vary with motivational and strategic considerations, and may be demonstrated to rank consistently on a scale of willingness to escalate, thus providing information about aggressive motivation. We conclude by identifying those features of avian threat displays that have not been adequately explained, in the hope that this reexamination of empirical data will help focus theoretical attention on these issues.
In a series of three experiments, we examined the hypothesis that female Japanese quail, Coturnix japonica, are motivated to form aggregations to reduce the probability of harassment by conspecific males. When in the presence of a conspecific male, female quail both sought others of their sex and remained near them. However, if no males were present, females were indifferent to or tended to avoid one another. We interpret these data as consistent with the hypothesis that one function of aggregations of female quail is to avoid harassment by conspecific males. Skew in male mating success would be a probable consequence of such aggregations of females. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.
Most animal communication has evolved and now takes place in the context of a communication network, i.e. several signallers and receivers within communication range of each other. This idea follows naturally from the observation that many signals travel further than the average spacing between animals. This is self evidently true for long-range signals, but at a high density the same is true for short-range signals (e.g. begging calls of nestling birds). This book provides a current summary of research on communication networks and appraises future prospects. It combines information from studies of several taxonomic groups (insects to people via fiddler crabs, fish, frogs, birds and mammals) and several signalling modalities (visual, acoustic and chemical signals). It also specifically addresses the many areas of interface between communication networks and other disciplines (from the evolution of human charitable behaviour to the psychophysics of signal perception, via social behaviour, physiology and mathematical models).
Despite the fact that most communication occurs in the context of networks of several individuals, the consequences of considering communication as a network on individuals' capacity for gathering information on congeners has been little investigated. Eavesdropping is the behaviour of a receiver extracting information from an interaction in which it is taking no part. Due to the fact that signals used in aggressive interactions are assumed to be reliable, eavesdropping could be an effective way of evaluating the quality of potential mates. We conducted two experiments designed to discover if female fighting fish (Betta splendens) monitor aggressive interactions between two males and if information gained by eavesdropping is used in the initial stages of subsequent mate choice. We found that females that had seen the interaction visited the winner first more often and spent significantly more time near, looking at and displaying to the winner of the interaction. By contrast females that had not seen the interaction visited the loser first more often and did not behave significantly differently to winner and loser. Overall these results are consistent with the idea that in the initial stages of mate choice females eavesdrop, i.e. use information gathered from male-male displays.
The aim of this study was to determine whether mothers' fear of human could influence the way young domestic Japanese quail respond to human. The first step was to obtain a set of adoptive mothers habituated-to-human (H mothers) and a set of adoptive mothers non-habituated-to-human (NH mothers). A set of 6-month-old adult females was handling daily for 15 successive days whereas another set of 6-month-old adult females received no visual or physical contact with human during the same period. We then obtained two sets of adoptive mothers non-divergent in tonic immobility (TI) duration but divergent by the amount of "fear" behaviour expressed towards human (human observer test, cage-plus-experimenter test). Then, we compared a set of young raised by H mothers to a set of young raised by NH mothers. Observations and tests were carried out both during the brooding period (between 5 and 12 days of age) and after separation from mothers (between 13 and 90 days of age). Our results revealed that young raised by H mothers were less fearful towards a static human (cage-plus-experimenter test, hand-on-home-cage-door-test) as well as towards a moving human (human observer test and capture test) than young raised by NH mothers. Nevertheless, as was found between the two sets of adoptive mothers, no clear differences were found between the two sets of young concerning general emotional reactivity (tonic immobility test, open field test and hole-in-the-wall test). These results reveal that young bird's emotional reactivity to human could be modulated by the mother and that this maternal influence remains detectable well after the end of maternal contact. (C) 2004 Elsevier B.V. All rights reserved.
Many experiments have tested the foraging behaviours of birds relative to their social status. However, results are still not completely clear about the relationship between foraging behaviour and social status in birds. Some studies have shown that dominants use subordinates as food finders, while others show the opposite. Whether dominants search by themselves or wait to exploit the findings of a subordinate is still an unanswered question. For testing these alternative hypotheses, we carried out a laboratory experiment that used female common domesticated canaries, Serinus canaria (L., 1758). We used strict female flocks to avoid any bias based on pair bonds. We looked at the foraging behaviours of females relative to their social status using a foraging board. Our results showed that dominant females behaved as their own food finder. They began searching in the first position and had greater re-search behaviours, which allowed them to find seeds more rapidly than subordinates. Our study showed that foraging behaviour of dominants may be independent of the activities of subordinates. Our results also showed that there was no difference between the number of attacks received by dominants and subordinates when they were on the foraging board, which suggests that subordinates accessed the foraging board less frequently to avoid competition with dominants. We also suggest that environmental conditions may be one explanation for the differences observed among the different studies.
Fear can be a damaging stressor, resulting in impaired animal welfare and poor production economy. Often fear reactions are elicited in situations that are in some way related to predator defence. As males have a guarding role, mixing the sexes might be a way of reducing fear in large groups of laying hens. Tonic immobility (TI) and vigilance are anti-predator behaviours shown by poultry. They have been used in several studies to measure the level of fear or stress. The influence of males on duration of TI, vigilance and total number of behaviour transitions in female laying hens was studied on an egg production farm. Eight groups of 1200 white LSL layers each were used and 25 focal birds in each group were studied. In half of the groups one male per 100 females was added. The presence of males had a significant effect on TI-duration and frequency and duration of vigilant behaviour (P < 0.001); females in the mixed-sex groups had shorter TI-duration and showed less and shorter vigilance than females in the all-female groups. There was no significant effect on observed agonistic behaviour or the total number of behaviour transitions. However, significantly fewer females in the mixed groups had peck wounds on the comb. These results indicate that female laying hens show less signs of fear if the flock also contains males. (C) 2005 Elsevier B.V. All rights reserved.
The aim of this study was twofold: 1. To study the timing of copulation‐solicitation displays (CSD) in female canaries during a natural breeding cycle; 2. To address the question of the adequacy of invasive methods such as oestradiol treatment. Towards these ends, we compared seven oestradiol‐implanted and eight control females. Moreover, temporal relationships between reproductive behaviour and plasma concentrations of luteinizing hormone and oestradiol were investigated.
The results showed that: 1. CSD appeared about 3 d before egg laying, after the peak of nest building. The maximum number of CSD was observed at the beginning of egg laying. CSD disappeared when the last egg was laid, at the very beginning of incubation; 2. No significant difference was found between the two groups for any behavioural criterion, particularly CSD. No significant difference appeared between control and oestradiol‐treated females for luteinizing hormone concentrations. In contrast, oestradiol‐implanted females presented higher levels of oestradiol during nest building and during egg laying, 9–13 d after implantation (median 2.53 and 1.47 ng/ml for implanted females vs 0.57 ng/ml and undetectable levels for controls). Implantation had no effect on the progress of nest building, CSD exhibition, egg laying and incubation. Our results suggest that implantation with oestradiol is not necessary in female canary to obtain CSD since they breed readily in captivity and already have enough oestradiol. The similar results in both groups lead one to question the necessity of oestradiol priming in some female choice experiments.
Recent studies conducted in our laboratory have demonstrated that a special type of song phrase (‘sexy’ phrases) containing bipartite syllables composed of abrupt frequency falls and short silences stimulate female canaries to solicit for copulation. The study was undertaken to determine whether sexy phrases also facilitated other aspects of the reproductive activity of the female canary, namely, nest-building and egg-laying. During the first experiment, we studied the effect of sexy and non-sexy songs on copulation solicitation displays in 1-year-old females without reproductive experience and in mature females with previous reproductive experience. We confirmed that sexy songs elicited more sexual responses than did non-sexy songs in yearlings and in mature females. During the second experiment, we studied the effect of male songs on nest-building activities and egg-laying in 1-year-old inexperienced females, and in mature, experienced females. The songs of conspecific males significantly triggered and increased nest-building behaviour in female canaries whatever their age or reproductive experience. In contrast, song effects on egg-laying were only found in young females. One-year-old inexperienced females exposed to sexy or non-sexy songs laid more eggs and laid earlier than did 1-year-old inexperienced controls; no such differences were observed in mature, experienced females. The efficiency of songs in promoting nest-building or egg-laying appeared to be unrelated to their efficiency in eliciting sexual responses. No difference was found between females exposed to sexy songs and females exposed to non-sexy songs; differences were only found between control and the two groups of song-exposed females. This result demands further experiments in order to determine whether other song phrase types may account for the stimulating effects of male song on female nest-building and egg-laying.
In many species, symmetry enhances physical attractiveness of the face and body. In humans, facial attractiveness is also enhanced by symmetrical decoration in the form of facial paint [Cárdenas, R. A., & Harris, L. J. (2006)]. According to the good-genes hypothesis [e.g., Thornhill, R., & Gangestad, S. W. (1999)], symmetry is preferred because it is associated with mate quality. According to the receiver bias hypothesis [e.g., Enquist, M., & Johnstone, R. (1997)], it is a by-product of how the visual system is designed. Proponents of the good-genes hypothesis have suggested that a preference for symmetry may vary with fertility, namely, that it will be enhanced in women in the high-fertility phase of the menstrual cycle. Previous research does demonstrate that, during this phase, women prefer the scent of more symmetrical men [e.g., Gangestad, S. W., & Thornhill, R. (1998)]. However, research employing assessment of faces fails to find a similar effect [Koehler, N., Rhodes, G., & Simmons, L. W. (2002)]. Previous research asked subjects to judge faces one at a time during high fertility (around ovulation) and low fertility (menstruation). We used a different face-presentation method, tested women during the other low-fertility (midluteal) phase, and used decorated as well as undecorated faces. As in our prior study [Cárdenas, R. A., & Harris, L. J. (2006)], symmetry of facial features and symmetry of decoration enhanced attractiveness, but, contrary to the possible prediction of the good-genes hypothesis, the effects did not vary across the cycle. The results as they are, therefore, can be equally accommodated by both hypotheses.
Male birds with bright plumage colors which entail production costs and increased predation risks should be able to emphasize the handicap function of their ornaments when they present themselves against a contrasting background. Contrast with the background may accentuate the signal's costliness and make the male more conspicuous to predators. Both effects should contribute to increase male attractiveness. It is therefore conceivable that the extent to which the male plumage contrasts against the background modifies female choice behavior as it improves the discrimination of mates. We tested this hypothesis in domesticated canaries (Serinus canaria). In the first experiment, yellow females could choose between two yellow males presented in front of a yellow and a white background, respectively. In the second experiment we replaced the yellow males with white ones. In experiment 1 females associated significantly more with yellow males which contrasted strongly against the white background. In experiment 2 there was at least a trend for preferred associations with the white male in front of the yellow background. We found no support that male properties per se were chosen. We could further clarify that females associated with the contrasting male and not with a particular background color. Thus, our study demonstrates that not only inherent properties of the sender but also the interaction of bird color with the signaling environment may influence mate choice.
Communication and social behaviour are inextricably linked, with communication mediating important social behaviours such
as resource defence and mate attraction. However, the social environment in which communication occurs is often ignored in
discussions of communication behaviour. We argue that networks of several individuals are the common social environment for
communication behaviour. The consequences for receivers and signallers of communicating in a network environment are the main
subjects of this review. Eavesdropping is a receiving behaviour that is only possible in the environment of a network and
therefore we concentrate on this behaviour. The main effect of communication networks on signallers is to create competition
with other signallers for receiver attention. We discuss the consequences of such competition. To conclude, we explore the
role of signals and signalling interactions as sources of information that animals exploit to direct their behaviour.
It has been shown that duration of tonic immobility (TI) reflects predation risk and levels of fearfulness. Since the chances of escaping predation are higher in larger groups, birds from these groups should have shorter TI duration. On the other hand, increased competition between birds in larger groups might lead to greater fearfulness and longer TI in larger groups. The aim of this study was to test these two hypotheses. Laying hens raised in floor pens in group sizes of 15, 30, 60 and 120, each with four replicates, were used. Tonic immobility tests were performed on adult birds, either directly ‘in’ their home pen or ‘out’ in a separate room. In the test ‘in’, duration of TI increased with group size, with a significant difference between group sizes 15 and 120 (P=0.012). In the test performed ‘out’, there was a trend for TI to be longer in larger groups. The duration of TI in groups tested ‘in’, was significantly shorter than in groups tested ‘out’ (P<0.00l). The results of this study suggest that although the ultimate function of TI is to reduce predation, the social environment is a proximate factor affecting TI duration in domestic hens.
Abstract. In most monogamous birds copulation frequency peaks a few days before the start of egg laying and then either ceases or drops markedly. This decline occurs despite the fact that females remain fertile until the day their penultimate egg is laid. Several hypotheses to explain the decline in copulation frequency following the onset of egg laying were tested, using data from different species. There was no evidence that the decline was a consequence of (1) one or other partner being involved in incubation and hence unavailable to copulate, (2) male partners being unavailable because they were seeking extra-pair copulations, (3) there being fewer eggs to fertilize as egg laying proceeds, (4) offspring from late hatched eggs being of lower value, or (5) copulations being costly in terms of the risks of damage to unlaid eggs. There were insufficient data to test (6) the egg-predation hypothesis: that for species that copulate at or near their nest those vulnerable to egg predation should cease copulation relatively early in their cycle. The hypothesis (7) that copulations were less efficient once egg laying has started was supported, as was (8) the sperm competition hypothesis across different mating systems. Where there is little sperm competition, as in lekking species, copulation ceases very early, but with intense sperm competition, as in simultaneously polyandrous species, copulations continue until the end of the female's fertile period. In polyandrous species continued copulation may benefit both sexes: males because it increases their probability of fathering offspring, and females because by continuing to copulate they obtain material benefits (paternal care) from their male partners. With intermediate sperm competition (monogamy) copulation shows an intermediate pattern, but within monogamous birds factors, as yet unidentified, affect the temporal pattern of copulation. In most birds copulation frequency is controlled by the female: a female requires only a single insemination to fertilize her eggs. Male interests differ: because of last male sperm precedence, males benefit from more frequent copulation and over a longer period to ensure their paternity. Within species this conflict between the sexes is evident from the temporal pattern of female- and male-initiated copulations.
Both male and female birds are known to eavesdrop on male–male vocal interactions. In contrast, males visually eavesdropping on male–male contests has been observed in fish but only suggested in birds and few avian studies have been done. We observed the behaviour of male domestic canaries, Serinus canaria, during competition for food with rivals they had or had not previously observed in dyadic contests. Males responded differentially to winners and losers of agonistic interactions they had witnessed, initiating fewer attacks against the winner and spending less time foraging. In contrast, no such effect was found when males had no prior knowledge of the relative competitive ability of the contestants. The domestic canary is, to our knowledge, the only species proven to use both visual and acoustic cues to eavesdrop.
It is generally believed that success in male–male competition genuinely reflects high quality and that female preference for dominant males should therefore be widespread. However, recent studies suggest that male dominance is not always attractive and that it does not necessarily predict superior parental quality, better genes or other forms of benefit to females. In fact, the costs of choosing a dominant male can sometimes outweigh the benefits. When traits selected by male–male competition do not reflect overall mate quality, females are expected to use other choice cues and might occasionally prefer subordinate males. Thus, male–male competition and female choice can sometimes work in different, or even opposing, directions.
The growth of bird song research over the past half century has been catalysed by both technical and theoretical advances. The study of mechanisms has largely moved to the neurobiological level, where work on bird song has blossomed. At the behavioural level, development and function have been the prime foci of attention, and I briefly review the advances in these two areas. But, looking forwards, the well is far from dry: I suggest a few topics on which I expect that papers will appear in the journal in the next few decades. Copyright 2003 Published by Elsevier Science Ltd on behalf of The Association for the Study of Animal Behaviour.
Songbirds can vary the timing of song production with respect to other singing individuals on a song-by-song timescale, for example birds may overlap songs or alternate singing and thereby avoid overlap. Playback was used to study the information contained in such timing of song exchanges in territorial male robins,Erithacus rubeculaThe results are consistent with the idea that interacting with a singer either by overlapping or alternating is a way of indicating the intended receiver whereas non-interactive (loop) playback does not give this information. Furthermore, an overlapping pattern of singing generally elicited responses characteristic of highly aroused males. In robins this is shown by a rapid approach and change to an almost continuous, low amplitude pattern of singing referred to as twittering. Thus overlapping could be taken as indicating a high degree of arousal or a willingness to escalate. The response changed during the experimental period, with twittering responses becoming more common regardless of playback treatment. This result is consistent with experimental males having gathered information from interactions between playback and their neighbours in previous trials, that is, they collected information by eavesdropping.
As a test of the automaticity of the food calling behaviour of cockerels, their sensitivity to the presence and nature of an audience was explored. Males were presented with either a highly preferred food or a non-food item in the presence of a familiar female, a strange female, a male, or with no audience at all. With food as a referent, there was significantly less food calling with no audience than in the presence of females, and even less with a male as a potential receiver. There was a significant amount of calling for the non-food item, especially in the presence of a strange female. Food calling to non-foods in certain social contexts is discussed as a case of deception. The modulation of signal production according to the nature of the receiver is considered in relation to the issue of intentionality in animal communication.
The sexual responsiveness of female canaries, Serinus canaria, to six different types of male song phrases extracted from natural song was tested. Copulation solicitation displays were used as an index of female sexual response. Playbacks were performed several days before and during egg laying (a period of natural sexual responsiveness of the females to song). Female canaries were especially responsive to particular short phrases whose essential features were abrupt frequency fall and short silences. This differential responsiveness occurred whatever the serial position (beginning, middle or end) of the phrase in the song and its serial relationship to other different conspecific phrases as well as the general song context (conspecific or heterospecific phrases). Influences such as early experience or ‘sensory bias’ that may lead to a particular sexual sensitivity of female canaries to these types of song phrases are discussed.