Brief increases in corticosterone affect morphology, stress responses, and telomere length, but not post-fledging movements, in a wild songbird

Organisms are frequently exposed to challenges during development, such as poor weather and food shortage. Such challenges can initiate the hormonal stress response, which involves secretion of glucocorticoids. Although the hormonal stress response helps organisms deal with challenges, long-term exposure to high levels of glucocorticoids can have morphological, behavioral, and physiological consequences, especially during development. Glucocorticoids are also associated with reduced survival and telomere shortening. To investigate whether brief, acute exposures to glucocorticoids can also produce these phenotypic effects in free-living birds, we exposed wild tree swallow (Tachycineta bicolor) nestlings to a brief exogenous dose of cort once per day for five days and then measured their morphology, baseline and stress-induced corticosterone levels, and telomere length. We also deployed radio tags on a subset of nestlings, which allowed us to determine the age at which tagged nestlings left the nest (fledged) and their pattern of presence and absence at the natal site during the post-breeding period. Corticosterone-treated nestlings had lower mass, higher baseline and stress-induced corticosterone, and reduced telomeres; other metrics of morphology were affected weakly or not at all. Our treatment resulted in no significant effect on survival to fledging, fledge age, or age at first departure from the natal site, and we found no negative effect of corticosterone on inter-annual return rate. These results show that brief acute corticosterone exposure during development can have measurable effects on phenotype in free-living tree swallows. Corticosterone may therefore mediate correlations between rearing environment and phenotype in developing organisms, even in the absence of prolonged stressors.Comment: 35 pages, 4 figures, 1 appendi

Full lifetime perspectives on the costs and benefits of lay date variation in tree swallows

Animals must balance various costs and benefits when deciding when to breed. The costs and benefits of breeding at different times have received much attention, but most studies have been limited to investigating short-term season-to-season fitness effects. However, breeding early, versus late, in a season may influence lifetime fitness over many years, trading off in complex ways across the breeder?s lifepan. In this study, we examined the complete life histories of 867 female tree swallows (Tachycineta bicolor) breeding in Ithaca, New York, between 2002 and 2016. Earlier breeders outperformed later breeders in short-term measures of reproductive output and offspring quality. Though there were weak indications that females paid long-term future survival costs for breeding early, lifetime fledgling output was markedly higher overall in early-breeding birds. Importantly, older females breeding later in the season did not experience compensating life-history advantages that suggested an alternative equal-fitness breeding strategy. Rather, most or all of the swallows appear to be breeding as early as they can, and differences in lay dates appear to be determined primarily by differences in individual quality or condition. Lay date had a significant repeatability across breeding attempts by the same female, and the first lay date of females fledged in our population was strongly influenced by the first lay date of their mothers, indicating the potential for ongoing selection on lay date. By examining performance over the entire lifespan of a large number of individuals, we were able to clarify the relationship between timing of breeding and fitness and gain new insight into the sources of variability in this important life history trait.Fil: Winkler, David Ward. Cornell University; Estados UnidosFil: Hallinger, Kelly K.. Cornell University; Estados UnidosFil: Pegan, Teresa M.. University of Michigan; Estados UnidosFil: Taff, Conor C.. Cornell University; Estados UnidosFil: Verhoeven, Mo A.. University of Groningen; Países BajosFil: Van Oordt, David Chang. Cornell University; Estados UnidosFil: Stager, Maria. University of Montana; Estados UnidosFil: Uehling, Jennifer J.. Cornell University; Estados UnidosFil: Vitousek, Maren N.. Cornell University; Estados UnidosFil: Andersen, Michael J.. University of New Mexico; Estados UnidosFil: Ardia, Daniel R.. Franklin & Marshall College; Estados UnidosFil: Belmaker, Amos. Tel Aviv University; IsraelFil: Ferretti, Valentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Forsman, Anna M.. University Of Central Florida; Estados UnidosFil: Gaul, Jennifer R.. International High School at La Guardia Community College; Estados UnidosFil: Llambias, Paulo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Orzechowski, Sophia C.. Harvard University; Estados UnidosFil: Shipley, Ryan. Max Planck Institute For Animal Behavior; AlemaniaFil: Wilson, Maya. Virginia Polytechnic Institute. Department Of Geological Sciences; Estados UnidosFil: Yoon, Hyun Seok. University of Tennessee; Estados Unido

A newly described call and mechanical noise produced by the Black-and-crimson Pitta Pitta ussheri

Volume: 29Start Page: 160End Page: 16

Negligible effects of blood sampling on reproductive performance and return rates of Tree Swallows

Blood sampling is a frequently used method of collecting genetic and physiological data in natural populations, and understanding the possible impact of blood sampling on individuals and populations is important, both for the welfare of study organisms and to avoid introducing bias into analyses using bled individuals. Most studies of birds have revealed minimal negative effects of blood sampling. However, Brown and Brown (2009. Auk 126: 853–861) found that blood sampling reduced return rates of Cliff Swallows (Petrochelidon pyrrhonota), suggesting that these results are not always generalizable and that swallows (Hirundinidae) may be particularly sensitive to blood sampling. We examined the possible effects of blood sampling on the reproductive performance of female Tree Swallows (Tachycineta bicolor) and the return rates of both females and offspring in a population in New York state. To reduce the chances of Type II error, we tested 15 possible effects of blood sampling on reproductive performance and return rates using generalized linear mixed models. Overall, our results suggest that blood sampling had few negative effects on within‐year reproductive success or survival of adult females. The one exception was that bleeding nestlings had a negative effect on the number of young that fledged in broods of five or six nestlings. Bleeding did not negatively impact return rates of females or nestlings in our Tree Swallow population. Our results support those of other studies suggesting that blood sampling has few negative effects on within‐year reproductive success or survival of adult females, and reiterate the importance of systematically testing for possible effects with datasets compiled over multiple years because such effects may be impossible to detect via direct monitoring during a single breeding season.ResumenEfectos despreciables de la toma de muestras de sangre en el desempeño reproductivo y las tasas de retorno de Tachycineta bicolorLa toma de muestras de sangre es un método frecuentemente usado para colectar datos genéticos y fisiológicos en poblaciones naturales y es importante entender el posible impacto de la toma de muestras de sangre sobre los individuos y las poblaciones, por ambas razones, el bienestar de los organismos de estudio y para evitar la introducción de sesgos a los análisis usando individuos sangrados. Muchos estudios en aves han revelado que los efectos negativos de la toma de muestras de sangre son mínimos. Sin embargo, Brown y Brown (2009. Auk 126: 853–861) encontraron que la toma de muestras de sangre reducía la tasa de retorno en Petrochelidon pyrrhonota, sugiriendo que estos resultados no son siembre generalizables y que las golondrinas (Hirundinidae) pueden ser particularmente sensibles a la toma de muestras de sangre. Examinamos los posibles efectos de la toma de muestras de sangre en el desempeño reproductivo de Tachycineta bicolor y las tasas de retorno en hembras y crías en una población en el estado de Nueva York. Para reducir los chances de error Tipo II, probamos 15 efectos posibles de la toma de muestras de sangre en el desempeño reproductivo y las tasas de retorno usando modelos lineales mixtos generalizados. En general, nuestros resultados sugieren que la toma de muestras de sangre tuvo pocos efectos negativos sobre el éxito reproductivo intra‐anual o las tasas de supervivencia de las hembras adultas. La única excepción fue que el sangrado de los pichones tuvo un efecto negativo en el numero de juveniles que salían del nido en las nidadas de cinco o seis pichones. El sangrado no tuvo ningún impacto negativo sobre las tasas de retorno de las hembras o de los pichones en nuestra población de Tachycineta bicolor. Nuestros resultados soportan esos otros estudios que sugieren que la toma de muestras de sangre tiene pocos efectos negativos sobre el éxito reproductivo intra‐anual o sobre la supervivencia de hembras adultas y reiteran la importancia de comprobar sistemáticamente los posibles efectos en las bases de datos recopiladas a través de múltiples años por que dichos efectos pueden ser imposibles de detectar por medio de monitoreos durante una única temporada de reproducción.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/148221/1/jofo12276_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/148221/2/jofo12276.pd

Solar-powered radio tags reveal patterns of post-fledging site visitation in adult and juvenile Tree Swallows Tachycineta bicolor.

The availability of small, lightweight tracking devices enhances our ability to study birds during mobile phases of their lives. Tree Swallows Tachycineta bicolor, a model species of wild songbird, are well-studied during their breeding season; but our understanding of their biology at other times of the year, when they are not tied to the fixed location of a nest, is more limited. We developed a lightweight radio tag with no battery (solar nanotag) to study the movements of small animals, and we deployed it to explore the behavior of Tree Swallows after the end of their summer breeding season. We tagged 32 breeding adult swallows and 36 juveniles and monitored their presence and absence at the breeding site during the post-fledging period. Although our observations are based on very small sample sizes, the tags revealed previously unknown patterns in Tree Swallow behavior during the post-breeding season. Some Tree Swallow fledglings continued to visit the site repeatedly in the months following the nesting season, with the latest detection occurring on September 30th; by contrast, all adults had permanently departed by the end of July. These results inform future hypotheses about post-breeding movements in Tree Swallows. But, more generally, the detection of tagged swallows on their distant wintering grounds, seven months after tagging, indicates the potential of studying small passerine movements throughout their entire lifetimes, and suggests a rich array of applications for these "Life Tags" to study the movements of small animals world-wide

Asymmetric Response of Costa Rican White-Breasted Wood-Wrens (Henicorhina leucosticta) to Vocalizations from Allopatric Populations.

Divergence in song between allopatric populations can contribute to premating reproductive isolation in territorial birds. Song divergence is typically measured by quantifying divergence in vocal traits using audio recordings, but field playback experiments provide a more direct way to behaviorally measure song divergence between allopatric populations. The White-breasted Wood-Wren (Henicorhina leucosticta; hereafter "WBWW") is an abundant Neotropical species with four mitochondrial clades (in Central America, the Darién, the Chocó and the Amazon) that are deeply divergent (~5-16% sequence divergence). We assessed the possibility that the WBWW as currently defined may represent multiple biological species by conducting both statistical analysis of vocal characters and field playback experiments within three clades (Central America, Chocó and Amazon). Our analysis of vocal traits revealed that Central American songs overlapped in acoustic space with Chocó songs, indicating vocal similarity between these two populations, but that Central American songs were largely divergent from Amazonian songs. Playback experiments in the Caribbean lowlands of Costa Rica revealed that Central American WBWWs typically responded aggressively to songs from the Chocó population but did not respond to playback of songs from the Amazonian population, echoing the results of the vocal trait analysis. This marked difference in behavioral response demonstrates that the songs of Central American and Amazonian WBWWs (but not Central American and Chocó WBWWs) have diverged sufficiently that Central American WBWWs no longer recognize song from Amazonian WBWWs as a signal to elicit territorial defense. This suggests that significant premating reproductive isolation has evolved between these two populations, at least from the perspective of the Central American population, and is consistent with the possibility that Central American and Amazonian populations represent distinct biological species. We conclude by advocating for the further use of field playback experiments to assess premating reproductive isolation (and species limits) between allopatric songbird populations, a situation where behavioral systematics can answer questions that phylogenetic systematics cannot

Rapid adjustments of migration and life history in hemisphere-switching cliff swallows

Many aspects of bird migration are necessarily innate.1 However, the extent of deterministic genetic control, environmental influence, and individual decision making in the control of migration remains unclear.2–8 Globally, few cases of rapid and dramatic life-history changes resulting in novel migration strategies are known. An example is latitudinal trans-hemispheric breeding colonization, whereby a subpopulation suddenly begins breeding on its non-breeding range.9–13 These life-history reversals demand concomitant changes in the timing of migration, feather molt, and breeding if the population is to remain viable.13 Cliff swallows, Petrochelidon pyrrhonota, are long-distance migrants that breed in North America and spend the non-breeding season mostly in South America.14 However, in 2015, a small population switched hemispheres by breeding successfully in Argentina,9 over 8,000 km from the nearest potential source, after presumably failed attempts.15,16 This provided a unique chance to characterize the early mechanisms of change in migratory behavior and phenology and to assess the possibility of double breeding. We tracked cliff swallows with geolocators following their second and fourth breeding seasons in Argentina, documenting inverted seasonality, three new migratory patterns and non-breeding areas (North America, Mesoamerica, and South America), and a shift of molt phenology by approximately 6 months, all possibly arising within a single generation. These birds did not practice migratory double breeding, although some spent the boreal summer in the traditional breeding range. Our data show that fundamental phenological changes occurred very rapidly during colonization and that phenotypic plasticity can underlie profound changes in the life histories of migratory birds.Fil: Areta, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del Noroeste Argentino. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto de Bio y Geociencias del Noroeste Argentino; ArgentinaFil: Salvador, Sergio A.. Investigador Autónomo; ArgentinaFil: Gandoy, Facundo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico NOA Sur. Instituto de Ecología Regional. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto de Ecología Regional; ArgentinaFil: Bridge, Eli S.. University of Oklahoma. Oklahoma Biological Survey; Estados UnidosFil: Gorleri, Fabricio Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Bio y Geociencias del Noroeste Argentino. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto de Bio y Geociencias del Noroeste Argentino; ArgentinaFil: Pegan, Teresa M.. Cornell University; Estados Unidos. University of Michigan; Estados UnidosFil: Gulson Castillo, Eric R.. Cornell University; Estados Unidos. University of Michigan; Estados UnidosFil: Hobson, Keith A.. Western University; CanadáFil: Winkler, David Ward. Cornell University; Estados Unido

Summary of subspecies and their clades based on [21].

<p>Birds from western Colombia are presumed to be within the Chocó clade pending further evidence.</p

Spectrograms showing representative song phrases from White-breasted Wood-Wren populations.

<p>(A) Central American (Costa Rica, ML3922); (B) Amazon (ML46962); and (C) Chocó (XC17276).</p

Percent of individuals approaching the speaker in each experiment.

<p>Responses to the Amazon experiment are on the left and responses to the Chocó experiment are on the right. Note that sympatric trials serve as positive controls (wrens approached the speaker in all sympatric trials).</p