Viviana Massoni

• University of Buenos Aires

ABSTRACT. We studied the return rate, apparent survival, and probability of recapture of the Saffron Finch (Sicalis flaveola pelzelni), a thraupid with sexual dichromatism and age-related male feather phenotypes; the second-year males are dull and indistinguishable from females to humans and conspecifics alike, whereas the after second year males a...

In many avian species, age, body size, and song could signal quality or individual breeding experience and these traits are often correlated with reproductive success. The relationship between sexually selected signals and avian mating systems is a topic of active research, but still remains poorly investigated in species from southern latitudes. H...

Birds sing mostly to attract partners or to defend territories or resources. In relation to the first function, song can vary with age if older experienced males signal their quality through their vocal output. Regarding the second function, song can also vary with age if singing behavior helps mediate social interactions through repertoire sharing...

Extra-pair paternity rates vary markedly across avian taxa, but patterns of variation in this trait have been obscured by a paucity of data on closely related species, especially those spanning broad environmental gradients. Here we compare variation in extra-pair paternity rates among five species in the widespread swallow genus Tachycineta. Rates...

Thraupidae (Tanagers and allies) show a remarkable array of behaviors, ecologies, morphologies and plumage colors, offering a great opportunity to investigate the evolution of avian mating strategies. We characterize the population genetics and mating system of Sicalis flaveola pelzelni, a socially monogamous Neotropical songbird with biparental ca...

Sexually dichromatic birds often show delayed plumage maturation, but second-year (SY) males may or may not be distinguishable from females. In competitive contexts, SY males receive a reduced amount of adult males’ aggression, either by mimicking females or through signaling their sex and inexperience as subordinate males. To the human eye, reprod...

Ecological and physiological factors such as breeding density, breeding synchrony, and adult body condition can all affect extra-pair mating behavior, but the relative importance of these factors may vary among species. White-rumped Swallows (Tachycineta leucorrhoa) nesting in Buenos Aires Province, Argentina, exhibit high rates of extra-pair pater...

Empirical descriptions of vocal behaviour in avian communication are important in understanding its meaning and role in shaping the social and genetic relationships among individuals in a population. In this study, we provide the first detailed analysis of the vocal behaviour of the Saffron Finch (Sicalis flaveola pelzelni), a neotropical songbird...

In birds, the selection of nesting sites and mates has a profound influence on the daily interactions of individuals. Both behaviours are energetically costly and time-consuming and can strongly affect the Darwinian fitness of individuals. Using a 12-year dataset on banded returning breeders, we explored variables associated with nest-box choice an...

In a study of almost 16 000 nest records from seven swallow species across the entire Western Hemisphere, clutch sizes decline with relative laying date in each population, but the slope of this decline grows steeper with increasing distance from the equator. Late-laying birds at all latitudes lay clutches of similar sizes, suggesting that latitudi...

Life history traits exhibit substantial geographical variation associated with the pace of life. Species with a slow pace are expected to invest more in their future/residual reproductive value and are more common at tropical latitudes, whereas species from high latitudes, with a faster pace, are expected to prioritize the current reproductive effo...

Egg mass production is costly, but hatching from heavier eggs could be beneficial for the nestling's phenotype and fitness. Egg mass could be influenced by proximate causes, like food abundance, female condition, environmental conditions, and/or by ultimate causes, such as females depositing resources differentially within a clutch to increase the...

In temperate regions of the Southern Hemisphere, avian parental care is understudied, in particular for the neotropical family Furnariidae. We measured rates of nest building, mud carrying, incubation, brooding, feeding, and nest-sanitation behaviors of molecularly sexed Rufous Horneros (Furnarius rufus) nesting in the humid pampas of Argentina. We...

Many animals use photoperiod cues to synchronize reproduction with environmental conditions and thereby improve their reproductive success. The circadian clock, which creates endogenous behavioral and physiological rhythms typically entrained to photoperiod, is well characterized at the molecular level. Recent work provided evidence for an associat...

Female birds that engage in extrapair mating may choose extrapair mates that are genetically compatible, increasing their fitness through genetic benefits, such as increased heterozygosity, to their offspring; or choose mates that are heterozygous at one or more loci. Here, we describe the extrapair mating system, explore the fitness benefits of ex...

The status signalling hypothesis states that conspicuous male plumage varies among males and serves as an honest signal of male quality and competitive ability. We expected immature-plumaged males of the Saffron Finch Sicalis flaveola to feed their incubating mates and nestlings and remove faecal sacs at lower rates than those of mature-plumaged ma...

Life-histories and demographic parameters of southern temperate bird species have been little studied. We estimated return rates between years and sexes, and adult apparent survival and recapture probabilities with mark–recapture data on White-rumped Swallows and found a lower return rate of unsuccessful females. There was little support for influe...

Resource allocation by female birds into their eggs may have important consequences on nestlings' life. Female's body condition, food abundance, environmental conditions, clutch size and lay date are some of the variables described to affect egg mass in Passeriformes. We studied the effect of those variables on egg mass of White-rumped Swallow (Tac...

We investigated whether the synchrony and proximity of nests of Yellow-winged Blackbirds (Agelaius thilius) provided protection against nest predation or brood parasitism by Shiny Cowbirds (Molothrus bonariensis). We analyzed the effect of the temporal aggregation of nests on the daily probability per nest of predation, desertion, egg punctures, an...

Parasitized hosts of the Shiny Cowbird (Molothrus bonariensis) suffer several costs, and among the most important is the loss of eggs through egg punctures inflicted by the parasite. Unparasitized nests also have eggs damaged by cowbirds, but researchers usually ignore these losses. To quantify this cost we compared three groups of nests of the Yel...

Nest-boxes used by the White-rumped Swallows, Tachycineta leucorrhoa leucorrhoa (Vieillot, 1817) [Aves: Hirundinidae] were sampled during two consecutive breeding seasons in the province of Buenos Aires, Argentina. A total of 11 taxa of insects were found in the nests of this species: 10 in the order Coleoptera: Coccinellidae [Cycloneda ancoralis;...

Nest-boxes used by the White-rumped Swallows, Tachycineta leucorrhoa leucorrhoa (Vieillot, 1817) [Aves: Hirundinidae] were sampled during two consecutive breeding seasons in the province of Buenos Aires, Argentina. A total of 11 taxa of insects were found in the nests of this species: 10 in the order Coleoptera: Coccinellidae [Cycloneda ancoralis;...

Despite being a common and widespread species, the White-rumped Swallow (Tachycineta leucorrhoa) is one of the least-studied members of its genus. We examined the rates of nest-visitation and nest-sanitation of male and female White-rumped Swallows during the nestling period, in 23 nests, and compared them with those of the extensively studied Tree...

FIGURE 1. Geographic distribution of Tachycineta leucorrhoa in South America (modified from InfoNature 2004). Locality where the insect fauna in the nestboxes was sampled is indicated by a red dot.

FIGURE 2. Seasonal variation of prey item found in nests of Tachycineta leucorrhoa from Argentina, Buenos Aires province, during the 2005 – 2006 breeding season. See explanation in the text (section III. Swallows’ prey and insects mentioned as associated to swallows’ nests).

Nestling development in altricial birds is associated with the age at which nestlings acquire the ability to thermorregulate, and the environment and nest temperatures. The aim of this study was to determine the effect of the number of chicks and the air temperature in the development of the chicks of a secondary cavity nester, the Saffron Finch, S...

We conducted a study of the breeding biology of the White-rumped Swallow Tachycineta leucorrhoa nesting in nestboxes in a flat, farming landscape in Buenos Aires Province, Argentina. White-rumped Swallow nesting attempts were detected from the end of September to mid December, with most clutches laid during October. Birds laid clutches of 4–6 eggs...

ABSTRACT Swallows and martins are infrequent hosts of the generalist brood parasite Shiny Cowbird (Molothrus bonariensis). We monitored 50 nesting attempts by White-rumped Swallows (Tachycineta leucorrhoa) over a two-year period in Argentina and detected low rates of brood parasitism (three nests, or 6%). Of the three nests parasitized, cowbirds (N...

Dimorfismo sexual y cuidado parental en el Varillero Ala Amarilla (Agelaius thilius).

La arquitectura de los nidos de la Golondrina Ceja Blanca (Tachycineta leucorrhoa) no ha sido descripta en detalle hasta el momento y posiblemente varíe con las dimensiones de la cavidad en la cual son construidos. Se describen las etapas de la construcción, la arquitectura y los elementos que componen los nidos de esta especie en cajas nido de igu...

IMPACT OF BROOD PARASITISM BY SHINY COWBIRDS (MOLOTHRUS BONARIENSIS) ON THE REPRO- DUCTIVE SUCCESS OF THEIR HOSTS.— We present a review of the impact of brood parasitism by Shiny Cowbirds (Molothrus bonariensis) on the reproductive success of their hosts. We analysed the ef- fect of parasitism on nest survival and on egg survival, hatching success...

Parasitized hosts of the Shiny Cowbird (Molothrus bonariensis) suffer several costs, and among the most important is the loss of eggs through egg punctures inflicted by the parasite. Unparasitized nests also have eggs damaged by cowbirds, but researchers usually ignore these losses. To quantify this cost we compared three groups of nests of the Yel...

We investigated whether the synchrony and proximity of nests of Yellow-winged Blackbirds (Agelaius thilius) provided protection against nest predation or brood parasitism by Shiny Cowbirds (Molothrus bonariensis). We analyzed the effect of the temporal aggregation of nests on the daily probability per nest of predation, desertion, egg punctures, an...

Parasitic cowbirds and cuckoos generally reduce the clutch size of the hosts they parasitize by removing or destroying some of their eggs. Shiny cowbirds (Molothrus bonariensis) puncture their hosts' eggs both when parasitizing the nests and also when they do not parasitize them. We propose that, by puncturing the host's eggs, shiny cowbirds gain a...

The shiny cowbird (Molothrus bonariensis) is a generalist brood parasite that lays either white-immaculate or spotted egg morphs in eastern Argentina and Uruguay. Some hosts accept both morphs, others accept spotted eggs and reject the white morph, but no host has been found to accept white eggs and reject spotted ones. It has been suggested that t...

Previous research on the habituation of the crab Chasmagnathus granulatus to an iterated visual danger stimulus disclosed two remarkable features of this mnemonic process: a) the ready acquisition and long-lasting nature of the habituated response, and b) the likely endogenous opioid modulation of the shortterm habituation, whose potential adaptive...