-
[show abstract]
[hide abstract]
ABSTRACT: The female nutrition hypothesis posits that provisioning intensity of incubating females by their mates may depend on female
needs and ensure proper incubation and a corresponding high hatching and breeding success of breeding pairs. Here, we have
handicapped female pied flycatchers Ficedula hypoleuca at the beginning of incubation by clipping two primaries on each wing and filmed nests during incubation and later nestling
provisioning to estimate male involvement in incubation feeding at the nest and in offspring care. Incubation feeding was
more frequent at late nests. Correcting for this seasonal effect, incubation feeding was significantly affected by treatment
and twice as high at experimental as at control nests. There was no effect of the experiment on female incubation attendance.
The handicap did not result in any effect on hatching and breeding success, nestling growth and male or female provisioning
and mass at the end of the nestling period. Males adjust their incubation feeding activity at the nest to female energetic
requirements during incubation.
KeywordsExperimental handicapping–Feather clipping–Incubation feeding–Nest attendance–Nestling provisioning–Parental condition
acta ethologica 05/2012; 14(2):85-89. · 1.35 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Previous studies have found strong relationships between calcium availability and eggshell pigmentation in the Great Tit (Parus major). According to the “structural function hypothesis”, protoporphyrins, the pigments responsible for reddish spots on speckled
eggs, are deposited in those areas of the shell where calcium deposition is less intense. In the study reported here, which
was carried out in three Blue Tit (Cyanistes caeruleus) populations in central Spain, we provide partial experimental support for the association between protoporphyrin eggshell
pigmentation and shell thinning. Contrary to our expectations, we did not observe a decrease in the size and intensity of
pigment spots for those eggs from calcium-supplemented nests. However, we did find that the provision of calcium-rich material
during the egg-laying period led to a more wide distribution of pigment spots and reduced the proportion of eggs with defective
shells (deviant pigmentation, dull and rough surface). When only the supplemented nests were considered in the analysis, within
the same clutch we also detected differences in the spotting distribution between those eggs laid by female Blue Tits observed
to have consumed calcium consumption on the day prior to laying and those observed not to have consumed calcium on the day
prior to laying. Clutch size was not affected by the calcium supplementation. Female Blue Tits experimentally supplied with
calcium-rich material had a shorter incubation period than control females, and they laid eggs with thicker shells. Eggshell
thickness markedly affects the probability of hatching and could explain the lower proportion of unhatched late eggs found
in supplemented nests in comparison with control ones. This study highlights the role of calcium in eggshell maculation and
its effects on breeding performance of small passerines. We found the spotting distribution to be a good predictor of calcium
deficiency. However, our results provide only mixed support for the “structural function hypothesis”: in our study populations,
the thickness of the eggshell was intimately associated with calcium availability, but the relationship between calcium and
protoporphyrin deposition remains far from clear.
KeywordsBlue Tit–Calcium availability–Eggshell pigmentation–Maculation–Speckled eggs
04/2012; 152(1):71-82.
-
[show abstract]
[hide abstract]
ABSTRACT: Glucocorticoids promote the mobilization of energy stores and they may facilitate the expression of energetically expensive
functions. Early arrival on the breeding grounds in migratory species and territorial competition are energetically demanding
activities that may be supported by elevated baseline glucocorticoid levels. Here, we evaluated the associations between the
baseline levels of excreted corticosterone (CORT) metabolites of male Pied Flycatchers (Ficedula hypoleuca) just after arriving on their breeding area and timing of arrival, considering ornamental traits indicative of social status,
like forehead patch size and black plumage coloration, as well as heat shock protein levels (HSP60). We observed a positive
association of CORT metabolites with HSP60 levels, which are synthesized under several environmental challenges affecting
cell homeostasis. Our data showed a negative association between arrival date and CORT metabolite levels, possibly as a result
of the higher energetic demands imposed by the hard environmental conditions experienced at the time of an early arrival after
migration. We observed a negative relationship of forehead patch dimensions and CORT metabolite levels, suggesting that dominance
is associated with low baseline CORT metabolites. Also, males that expressed a higher degree of territorial behaviour when
exposed to a playback song of a conspecific at their nest-box showed higher CORT metabolites upon arrival than males that
expressed a lower degree of territorial behavior. This may indicate that elevated baseline CORT metabolite levels may facilitate
an intense territorial competition in males. Thus, male–male competition may be a factor affecting observed baseline glucocorticoid
levels in migratory birds.
KeywordsArrival date-Glucocorticoid-Heat shock proteins-Forehead patch-Territorial behavior
04/2012; 151(3):587-597.
-
[show abstract]
[hide abstract]
ABSTRACT: Melanin-based plumage ornaments may express individual quality in the context of social and sexual selection. Oxidative stress and antioxidant defences may be expressed through melanin-based plumage traits. Male Pied Flycatchers Ficedula hypoleuca exhibit eumelanic dorsal plumage and white feather patches on forehead and wing feathers. Although these traits have been related to sexual selection in some populations, no physiological correlate of variation in these characters has been previously shown. Here we test if these plumage traits are related to plasma oxidative stress and antioxidant capacity. We captured males while feeding nestlings in a population breeding at high altitude (1200–1400 m) in central Spain and collected blood samples from brachial veins. Percentage black on dorsal plumage and extension of white on folded wing and forehead were obtained from digital photographs. Plasma samples were analysed in the laboratory to obtain lipid peroxidation as a measure of oxidative damage by quantifying malondialdehydes (MDA), and antioxidant capacity. When controlling for male mass, breeding date and brood size, only forehead patch size was negatively associated with plasma lipid peroxidation levels and positively related to antioxidant capacity. There was no association among different plumage traits. Thus forehead patch size in montane Iberian populations may signal male phenotypic quality through plasma oxidative stress and antioxidant capacity possibly due to altitudinal effects on oxidative stress.
Acta Ornithologica 09/2011; · 1.23 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Salmonella and Yersinia are important enteropathogens in poultry and can affect birds of all ages, including embryos. These food-borne zoonotic enteropathogens are of great economic and medical concern worldwide and are intensely studied in poultry. Information regarding the prevalence of these bacteria in wild birds is scarce and biased toward avian species ecologically linked to humans, which have often been incriminated as both reservoirs and disseminators of these enteropathogens. The prevalence of Salmonella and Yersinia recovered from both the feces and eggs in a population of female pied flycatchers (Ficedula hypoleuca) breeding in nest-boxes in central Spain was evaluated. Salmonella arizonae was recovered from the feces of one female but was not recovered from eggs. Yersinia was not detected in either the feces or eggs. These results may suggest that Salmonella and Yersinia may be uncommon in this population studied and may indicate that these birds are unlikely reservoirs of Salmonella and Yersinia.
Journal of Zoo and Wildlife Medicine 06/2011; 42(2):313-6. · 0.38 Impact Factor
-
Tapio Eeva,
Suvi Ruuskanen,
Juha-Pekka Salminen,
Eugen Belskii,
Antero Järvinen,
Anvar Kerimov,
Erkki Korpimäki,
Indrikis Krams, Juan Moreno,
Chiara Morosinotto,
Raivo Mänd,
Markku Orell,
Anna Qvarnström,
Heli Siitari,
Fred M Slater,
Vallo Tilgar,
Marcel E Visser,
Wolfgang Winkel,
Herwig Zang,
Toni Laaksonen
[show abstract]
[hide abstract]
ABSTRACT: Carotenoids in the egg yolks of birds are considered to be important antioxidants and immune stimulants during the rapid growth of embryos. Yolk carotenoid composition is strongly affected by the carotenoid composition of the female's diet at the time of egg formation. Spatial and temporal differences in carotenoid availability may thus be reflected in yolk concentrations. To assess whether yolk carotenoid concentrations or carotenoid profiles show any large-scale geographical trends or differences among habitats, we collected yolk samples from 16 European populations of the pied flycatcher, Ficedula hypoleuca. We found that the concentrations and proportions of lutein and some other xanthophylls in the egg yolks decreased from Central Europe northwards. The most southern population (which is also the one found at the highest altitude) also showed relatively low carotenoid levels. Concentrations of β-carotene and zeaxanthin did not show any obvious geographical gradients. Egg yolks also contained proportionally more lutein and other xanthophylls in deciduous than in mixed or coniferous habitats. We suggest that latitudinal gradients in lutein and xanthophylls reflect the lower availability of lutein-rich food items in the northern F. hypoleuca populations and in montane southern populations, which start egg-laying earlier relative to tree phenology than the Central European populations. Similarly, among-habitat variation is likely to reflect the better availability of lutein-rich food in deciduous forests. Our study is the first to indicate that the concentration and profile of yolk carotenoids may show large-scale spatial variation among populations in different parts of the species' geographical range. Further studies are needed to test the fitness effects of this geographical variation.
Oecologia 02/2011; 165(2):277-87. · 3.41 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Parasites are undoubtedly a biotic factor that produces stress. Heat shock proteins (HSPs) are important molecules buffering cellular damage under adverse conditions. During the breeding season, blue tit Cyanistes caeruleus (L.) adults are affected by blood parasites, nest-dwelling parasites and biting flies, potentially affecting their HSP-mediated responses. Here, we treated females with primaquine to reduce blood parasites and fumigated nests with permethrin to reduce nest-dwelling parasites to test whether these treatments affect HSP60 level during the breeding season. Medicated females, but not controls, had a significant reduction of the intensity of infection by Haemoproteus spp. blood parasites. However, final intensity of infection did not differ significantly between groups, and we did not find an effect of medication on change in HSP60 level. Fumigation reduced the abundance of nest-dwelling parasites (mites, fleas and blowfly larvae) and engorged biting midges in nests. Females breeding in non-fumigated nests increased HSP60 levels during the season more than those breeding in fumigated nests. Furthermore, the change in HSP60 level was positively correlated with the abundance of biting midges. These results show how infections by nest ectoparasites during the breeding period can increase the level of HSPs and suggest that biting midges impose physiological costs on breeding female blue tits. Although plausible, the alternative that biting midges prefer to feed on more stressed birds is poorly supported by previous studies.
Naturwissenschaften 02/2011; 98(2):99-106. · 2.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Juveniles of many avian species possess a spotted or mottled body plumage that is visually distinct from the plumage of adults. In other species, however, juveniles fledge with a body plumage that is just a pale representation of adult female plumage. The reasons for this variation are poorly understood. Several hypotheses concerning social (parent–offspring, adult–juvenile, juvenile–juvenile), ecological (predation risk) and physiological (costs of plumage development) implications of juvenile body plumage are presented in relation to predictions concerning associations with certain ecological and life-history attributes of avian species. In the present study, we conduct a phylogenetically corrected comparative analysis of Western Palearctic passerines looking for sources of variation in the incidence of distinct and adult-like juvenile body plumages. We scored plumages based on plates in the Handbook of the Birds of the Western Palearctic (Cramp & Perrins, 1988–1994; Oxford University Press) (HBWP) and entered body mass, migratory habits, habitat, nestling diet, breeding dispersion, gregariousness, duration of the nestling period, type of nest, conspicuousness of female plumage, and sexual dimorphism as explanatory variables, as presented in HBWP, in phylogenetic generalized least square regression analyses. One-third of the species presented distinct juvenile body plumages, which lasted on average for the first 2 months of life. Body mass, conspicuousness of female plumage, migratory habits, and habitat were significantly associated with interspecific variation in distinctness of juvenile plumage, with smaller species, more conspicuous species, migrants, and species from forested habitats showing distinct juvenile plumages with higher frequency. The phylogenetic signal was moderately high. Assuming that conspicuous adult plumage is costlier to produce than distinct juvenile body plumage (pigments, conspicuousness), the need to acquire social status among juveniles before the winter may explain the more adult-like plumage in resident species because juveniles will probably compete with individuals that they may have known during their first months of life. On the other hand, migrant juveniles may compete with a different set of individuals in winter quarters and can use savings in resources necessary for developing adult-like plumages to improve migration capacity by allocating resources to other functions. The association with habitat could be related to juveniles in open habitats participating in more extended interactions with other juveniles than in forested habitats where lower visibility may reduce the capacity to detect or respond to signals from juvenile conspecifics. More studies on this possibly crucial life stage are needed. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102, 440–454.
Biological Journal of the Linnean Society 01/2011; 102(2):440 - 454. · 2.19 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Nest construction effort is seldom taken into account in avian life history studies, although activity duration and the amount of nest material collected may affect the condition of parent birds and their subsequent capacity to care for dependent offspring. In the present work, we reduced the effort needed to construct the nest in a cavity nester, the Pied Flycatcher Ficedula hypoleuca, where females are the main builders. To this end, we placed stored complete nests in certain nest-boxes as soon as nest building was initiated, whereas stored complete nests were placed in the control nests-boxes as soon as nest building had ceased. Thus, no nest-box contained the original nest. Pairs collected more nest material and for longer periods in the control nests, although the experimental pairs still added some nest material after the manipulation. Nest-boxes were filmed for 1 to 3 h during incubation and on days 4 and 11 of the nestlings' life. Female attendance during incubation was negatively affected by nest mass, this parameter explaining almost half the variation in attendance, which suggests an effect of nest mass on incubation efficiency. The female provisioning effort on day 4 was significantly higher in the experimental nests, whereas other parental care variables were affected by date, weather conditions and brood size or brood mass. Mean tarsus length at fledging was significantly longer in the experimental nests. The savings by females in nest construction effort were expressed in higher provisioning at early nestling stages and in improved nestling growth.
Acta Ornithologica 01/2011; · 1.23 Impact Factor
-
Suvi Ruuskanen,
Heli Siitari,
Tapio Eeva,
Eugen Belskii,
Antero Järvinen,
Anvar Kerimov,
Indrikis Krams, Juan Moreno,
Chiara Morosinotto,
Raivo Mänd,
Erich Möstl,
Markku Orell,
Anna Qvarnström,
Juha-Pekka Salminen,
Fred Slater,
Vallo Tilgar,
Marcel E Visser,
Wolfgang Winkel,
Herwig Zang,
Toni Laaksonen
[show abstract]
[hide abstract]
ABSTRACT: Reproductive, phenotypic and life-history traits in many animal and plant taxa show geographic variation, indicating spatial variation in selection regimes. Maternal deposition to avian eggs, such as hormones, antibodies and antioxidants, critically affect development of the offspring, with long-lasting effects on the phenotype and fitness. Little is however known about large-scale geographical patterns of variation in maternal deposition to eggs. We studied geographical variation in egg components of a passerine bird, the pied flycatcher (Ficedula hypoleuca), by collecting samples from 16 populations and measuring egg and yolk mass, albumen lysozyme activity, yolk immunoglobulins, yolk androgens and yolk total carotenoids. We found significant variation among populations in most egg components, but ca. 90% of the variation was among individuals within populations. Population however explained 40% of the variation in carotenoid levels. In contrast to our hypothesis, we found geographical trends only in carotenoids, but not in any of the other egg components. Our results thus suggest high within-population variation and leave little scope for local adaptation and genetic differentiation in deposition of different egg components. The role of these maternally-derived resources in evolutionary change should be further investigated.
PLoS ONE 01/2011; 6(11):e25360. · 4.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: While avian chronic haemoparasite infections induce reproductive costs, infection has not previously been shown to affect survival. Here, we experimentally reduced, through medication, the intensity of infection by Haemoproteus parasites in wild-breeding female blue tits Cyanistes caeruleus. However, this treatment did not reduce the intensity of infection in males or the intensity of infection by Leucocytozoon. Medicated females, but not males, showed increased local survival until the next breeding season compared with control birds. To our knowledge, this is the first empirical evidence showing long-term direct survival costs of chronic Haemoproteus infections in wild birds.
Biology letters 02/2010; 6(5):663-5. · 3.76 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Environmental factors may strongly affect avian-biting fly interactions in different ways because insects are heterothermic organisms that depend greatly on environmental variables to activate their metabolism and behaviour. We studied the effects of weather on both blackfly (Simuliidae) and biting midge Culicoides (Ceratopogonidae) abundance in nests of three passerine species: blue tits Cyanistes caeruleus, great tits Parus major and pied flycatchers Ficedula hypoleuca, breeding in the same area. We controlled for different host-related factors (hatching date, brood size and host species). Blackfly abundance was negatively related to minimum temperature. In addition, blackfly and biting midge abundances were negatively affected by wind speed measured at 07.00 h, but blackfly abundance was positively associated to wind speed at 18.00 h. We found higher blackfly and biting midge abundances in nests with larger broods breeding later in the season, and significantly higher biting midge abundance in pied flycatcher nests as compared to tit nests. These results represent, to our knowledge, the first report of both environmental and host-related effects on haematophagous fly abundance in the nests of wild hole-nesting birds.
Journal of Avian Biology 12/2009; 40(6):653 - 657. · 2.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Carotenoids are molecules that birds are not able to synthesize and therefore, must be acquired through their diet. These pigments, besides their function of giving birds red and yellow colouration when deposited in feathers, seem to act as immune-stimulators and antioxidants in the organism. Hence, only the healthiest individuals would be able to express carotenoid-based ornaments to a larger extent without compromising the physiological functions of carotenoids. Various studies have reported that birds infected by parasites are paler than those uninfected, but, to our knowledge, none of them has assessed the possible effect of multiple infections by blood parasites on plumage colour. By comparing the yellow colour in the breast plumage of blue tits, Cyanistes caeruleus, between birds infected by different numbers of blood parasite genera, we found that those birds infected by more than one genus were paler than those parasitized just by one. In addition, we examined the potential role of carotenoid-based plumage colour of blue tits as a long-term indicator of other parameters of health status, such as body condition and immunoglobulin and heat shock protein (HSP) levels. Our results indicate that more brightly coloured birds had lower HSP70 levels than paler birds, but we did not find any significant association between colour and body condition or immunoglobulin levels. In addition, we found a positive significant association between Haemoproteus density of infection and HSP60 levels. Overall, these results support the role of carotenoid-based colours as indicators of health status in blue tits and show detrimental effects of parasitism on this character.
Oecologia 11/2009; 162(4):825-35. · 3.41 Impact Factor
-
Paula K Lehtonen,
Toni Laaksonen,
Aleksandr V Artemyev,
Eugen Belskii,
Christiaan Both,
Stanislav Bures,
Andrey V Bushuev,
Indrikis Krams, Juan Moreno,
Marko Mägi,
Andreas Nord,
Jaime Potti,
Pierre-Alain Ravussin,
Päivi M Sirkiä,
Glenn-Peter Saetre,
Craig R Primmer
[show abstract]
[hide abstract]
ABSTRACT: The pied flycatcher is one of the most phenotypically variable bird species in Europe. The geographic variation in phenotypes has often been attributed to spatial variation in selection regimes that is associated with the presence or absence of the congeneric collared flycatcher. Spatial variation in phenotypes could however also be generated by spatially restricted gene flow and genetic drift. We examined the genetic population structure of pied flycatchers across the breeding range and applied the phenotypic Q(ST) (P(ST))-F(ST) approach to detect indirect signals of divergent selection on dorsal plumage colouration in pied flycatcher males. Allelic frequencies at neutral markers were found to significantly differ among populations breeding in central and southern Europe whereas northerly breeding pied flycatchers were found to be one apparently panmictic group of individuals. Pairwise differences between phenotypic (P(ST)) and neutral genetic distances (F(ST)) were positively correlated after removing the most differentiated Spanish and Swiss populations from the analysis, suggesting that genetic drift may have contributed to the observed phenotypic differentiation in some parts of the pied flycatcher breeding range. Differentiation in dorsal plumage colouration however greatly exceeded that observed at neutral genetic markers, which indicates that the observed pattern of phenotypic differentiation is unlikely to be solely maintained by restricted gene flow and genetic drift.
Molecular Ecology 10/2009; 18(21):4463-76. · 5.52 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Capsule Some males brought building materials to nests and females who were paired with such males laid heavier clutches.
Bird Study 07/2009; 56(2):264-267. · 0.87 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: En este trabajo exploramos dos de las varias hipótesis que se han propuesto para intentar explicar la variabilidad intraespecífica en el tamaño del nido. La hipótesis de la “termorregulación” propone que el tamaño del nido se optimizaría para mantener la temperatura de los huevos y minimizar las fluctuaciones de temperatura. Recientemente, se ha sugerido que el tamaño del nido podría reflejar el estado de salud o la calidad fenotípica de su constructor, actuando así como un carácter sujeto a selección sexual (hipótesis de la “señalización sexual”). Durante dos años, se registró el peso de los nidos de Cyanistes caeruleus de una población que nidifica en cajas-nido en el centro de España al inicio de la reproducción. Se registraron la fecha y tamaño de puesta, la duración del período de incubación y el éxito de eclosión. Se obtuvieron las medidas corporales y una muestra de sangre de las hembras adultas a los tres días de edad de los polluelos. Empleando modelos de regresión general controlando por las posibles variables que pudieran afectar al peso del nido, se encontró que la prevalencia de tripanosomas y el nivel de inmunoglobulinas de la hembra estuvieron significativamente relacionados con el peso del nido en uno de los años de estudio. Las hembras no infectadas por tripanosomas construyeron nidos más pesados que las infectadas, mientras que el nivel de inmunoglobulinas de la hembra estuvo negativamente relacionado con el peso del nido. El éxito de eclosión y la duración del período de incubación no estuvieron relacionados con el peso del nido en ninguno de los años de estudio. Por consiguiente, nuestros resultados no apoyan la hipótesis de la termorregulación, e indican que determinadas medidas de la salud de la hembra están relacionadas con el esfuerzo de construcción en algunos años, dependiendo probablemente de las condiciones ambientales.
The Auk 01/2009; · 2.16 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Le nombre des différents types de leucocytes en circulation dans le sang peut fournir de l'information au sujet de l'état de santé des oiseaux dans la nature. Nous avons compté le nombre et déterminé les proportions de leucocytes circulant dans des frottis sanguins provenant d'oisillons gobemouches noirs (Ficedula hypoleuca) peu de temps avant leur premier envol. Nous avons de cette façon étudié la relation entre ces mesures hématologiques et des facteurs environmentaux, comme le parasitisme, la masse corporelle, la date de l'éclosion et la taille de la couvée. Le rapport entre les leucocytes neutrophiles et les lymphocytes est plus élevé chez les oisillons dont les nids sont infestés par des mites et chez les individus les plus légers, les leucocytes neutrophiles étant les cellules sanguines qui se manifestent le plus lors d'une malnutrition. Les oiseaux qui ont recruté dans la population avaient des numérations de lymphocytes et de leucocytes neutrophiles moins élevées au stade de jeunes au nid que ceux qui n'ont pas recruté. Ainsi, la numération des leucocytes neutrophiles serait un meilleur prédicteur du recrutement local que d'autres variables féquemment utilisées, comme la masse corporelle ou la date d'éclosion. En somme, nous appuyons l'hypothèse que les numérations de leucocytes neutrophiles constituent de bons indicateurs de santé chez les oisillons. Nomenclature: Baker, 1956; Moss, 1968; Bennett, Peirce & Earle, 1994.
Ecoscience 01/2009; · 1.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: El dimorfismo sexual, el sistema de apareamiento y el cuidado parental solo se conocen para unas pocas especies de la gran familia de paseriformes Furnariidae. Realizamos un estudio del dimorfismo sexual en morfología, coloración y roles parentales durante la incubación y la crianza de los polluelos en Aphrastura spinicauda, un furnárido residente característico de los bosques lluviosos templados de Chile y Argentina. Por medio de sexado molecular, medidas morfológicas y análisis espectrofotométrico del plumaje corporal y de las rectrices de adultos reproductores capturados en la Isla de Chiloé (Chile meridional), determinamos que los machos eran entre un 2% y un 10% mayores que las hembras en peso y longitudes de tarso y ala, mientras no se encontraron diferencias en las longitudes del pico y de las dos rectrices centrales más largas a cada lado de la cola así como de las características espinas terminales de las rectrices. Machos pesados estuvieron emparejados con hembras pesadas y machos ligeros con hembras ligeras. Los machos participaron tanto como las hembras en todas las tareas reproductivas durante las fases de incubación y crianza, excepto en cuanto a la retirada de sacos fecales, en que las hembras se mostraron el doble de activas que los machos. En un estudio en la Isla de Navarino (extremo meridional de Chile) comprobamos que la larga y graduada cola con las rectrices terminando en espinas no fue empleada como soporte durante la búsqueda de alimento, por lo que podría estar implicada en alguna otra función como señalización sexual o social. La ausencia de dimorfismo sexual en plumaje y roles parentales en el Rayadito puede estar relacionada con la utilización de la larga cola como señal de calidad en ambos sexos, aunque esta hipótesis requiere confirmación a través de futuros estudios de elección de pareja.
The Condor 01/2009; · 1.12 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Un chevauchement temporel de la mue et de la reproduction peut être crucial pour les oiseaux migrateurs de longues distances puisque qu'ils sont restreints dans temps pour compléter ces fonctions énergivores avant le début de la migration. Cependant, des facteurs tels que les infections parasitaires du sang et le niveau de stress pouvant moduler le compromis potentiel entre la mue et la reproduction n'ont pas été étudié dans les populations sauvages d'oiseaux. Nous avons étudié l'existence d'un chevauchement de la mue et de la reproduction chez les femelles d'une population de gobemouche noir Ficedula hypoleuca en Espagne et la relation avec l'âge de la femelle, la prévalence de parasites du sang, le stress physiologique et la condition au début de la reproduction (à la phase d'incubation ou juste après l'éclosion) et aux derniers stades de la reproduction (les jours 11–12 de la période d'élevage). Les femelles nichant tardivement avaient plus de chance de présenter un chevauchement de la mue et de la reproduction que celles nichant hâtivement. L'âge de la femelle n'avait pas de lien avec le stade de mue lorsque la date de ponte et l'année d'étude étaient prises en considération. Une plus grande proportion de femelles infectées par Haemoproteus au début de période de reproduction démontraient un chevauchement de la mue et de la reproduction. La prévalence de Haemoproteus aux derniers stades de la reproduction ne différaient pas en fonction du stade de mue. Les femelles dont la mue et le reproduction se chevauchaient étaient aussi en meilleure condition et avaient des niveaux de stress (HSP60) moins élevés à la fin de la saison. Une plus grande proportion de femelles ayant mué sont retournées aux sites de reproduction la saison suivante en comparaison avec celles n'ayant pas mué. À l'opposé, les femelles en mue avaient un plus faible succès d'éclosion et moins d'oisillons à l'éclosion et à l'envol. Ainsi, le chevauchement de la mue et de la reproduction peut être l'expression d'un transfert dans l'allocation des ressources entre la reproduction présente et future vers une augmentation de l'entretien personnel au détriment de l'investissement reproductif.
Ecoscience 01/2009; · 1.28 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Although evidence is accumulating on the adaptive function of female ornamentation, very little is known about maternal allocation
decisions involving sexual signaling and other reproductive functions. Blue egg coloration has been suggested as a sexually
selected signal of female quality to males, and some recent studies are in accordance with this hypothesis. Blue eggshell
coloration results from the deposition of biliverdin pigment by laying females, which is a potent antioxidant. Thus, egg pigmentation
should be costly in terms of antioxidants, an assumption of the signaling hypothesis that has not been tested yet. We induced
increased reproductive effort in a set of female pied flycatchers Ficedula hypoleuca through nest removal and measured egg pigmentation and plasma antioxidant levels in relation with a control group. Experimental
females showed a negative association between egg color and plasma antioxidant levels, while there was no relationship for
control birds. This supports that egg pigmentation is costly in terms of general antioxidant defenses and suggests a tradeoff
between the allocations to both traits. Furthermore, experimental females with more colorful eggs raised more fledglings,
especially when breeding early. Controls did not show a relationship between egg color and reproductive success. Females laying
more colorful eggs could have shifted their allocation decisions towards current reproduction, at the expense of their own
antioxidant defenses. Our results highlight that blue egg coloration is a life-history trait, subject to tradeoffs with other
attributes, and seems to be especially informative under harsh breeding conditions.
Behavioral Ecology and Sociobiology 11/2008; 63(2):227-233. · 3.18 Impact Factor
