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5 April 2022 No apparent trade-off between the quality of nest-grown feathers and time spent in the nest in an aerial insectivore, the Tree Swallow
Conor C. Taff, Brianna A. Johnson, Allison T. Anker, Alyssa M. Rodriguez, Jennifer L. Houtz, Jennifer J. Uehling, Maren N. Vitousek
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Life history theory provides a framework for understanding how trade-offs generate negative trait associations. Among nestling birds, time spent in the nest, risk of predation, and lifespan covary, but some associations are only found within species while others are only observed between species. A recent comparative study suggests that allocation trade-offs may be alleviated by disinvestment in ephemeral traits, such as nest-grown feathers, that are quickly replaced. However, direct resource allocation trade-offs cannot be inferred from interspecific trait associations without complementary intraspecific studies. Here, we asked whether there is evidence for a within-species allocation trade-off between feather quality and time spent in the nest in Tree Swallows (Tachycineta bicolor). Consistent with the idea that ephemeral traits are deprioritized, nest-grown feathers had lower barb density than adult feathers. However, despite substantial variation in fledging age among nestlings, there was no evidence for a negative association between time in the nest and feather quality. Furthermore, accounting for differences in resource availability by considering provisioning rate and a nest predation treatment did not reveal a trade-off that was masked by variation in resources. Our results are most consistent with the idea that the interspecific association between development and feather quality arises from adaptive specialization, rather than from a direct allocation trade-off.


  • For many species of birds, nestlings hatch undeveloped and enter a period during which they must grow rapidly in the nest while also being exposed to a high risk of predation.

  • This intense period of growth can create strong trade-offs where a limited pool of resources must be invested into a variety of traits simultaneously.

  • One way that nestlings might balance these trade-offs is by withholding resources from traits that will have less influence on successful survival into adulthood.

  • We studied wild Tree Swallows to ask whether there is evidence for this direct investment trade-off by measuring fledging age, feather quality, and morphology while manipulating resource availability.

  • We did not find evidence for a direct trade-off within Tree Swallows, and we discuss how this result informs the interpretation of previous work comparing feather quality and development between species.

La teoría de la historia de vida proporciona un marco de referencia para comprender cómo las compensaciones generan asociaciones negativas entre los rasgos. Entre los polluelos que anidan, el tiempo que pasan en el nido, el riesgo de depredación y la esperanza de vida covarían, pero algunas asociaciones solo se encuentran dentro de las especies, mientras que otras solo se observan entre especies. Un estudio comparativo reciente sugiere que las compensaciones de asignación pueden aliviarse mediante la desinversión en características efímeras, como las plumas que crecen en el nido, que son rápidamente reemplazadas. Sin embargo, las compensaciones directas de asignación de recursos no pueden inferirse a partir de asociaciones de rasgos inter-específicos sin estudios intra-específicos complementarios. Aquí, nos preguntamos si hay evidencia de una compensación de asignación intra-específica entre la calidad de las plumas y el tiempo que pasan en el nido para Tachycineta bicolor. De acuerdo con la idea de que los rasgos efímeros no tienen prioridad, las plumas que creen en el nido tuvieron una densidad de barbas más baja que las plumas adultas. Sin embargo, a pesar de la variación sustancial en la edad de emplumamiento entre los polluelos, no hubo evidencia de una asociación negativa entre el tiempo en el nido y la calidad de las plumas. Además, tener en cuenta las diferencias en la disponibilidad de recursos al considerar la tasa de aprovisionamiento y un tratamiento de depredación de los nidos no reveló una compensación que estuviera enmascarada por la variación en los recursos. Nuestros resultados son mayormente consistentes con la idea de que la asociación inter-específica entre el desarrollo y la calidad de las plumas surge de una especialización adaptativa, más que de una compensación de asignación directa.

Copyright © American Ornithological Society 2022. All rights reserved. For permissions, e-mail:
Conor C. Taff, Brianna A. Johnson, Allison T. Anker, Alyssa M. Rodriguez, Jennifer L. Houtz, Jennifer J. Uehling, and Maren N. Vitousek "No apparent trade-off between the quality of nest-grown feathers and time spent in the nest in an aerial insectivore, the Tree Swallow," Ornithology 139(3), 1-13, (5 April 2022).
Received: 25 January 2022; Accepted: 29 March 2022; Published: 5 April 2022

aerial insectivore
asignación de recursos
calidad de las plumas
developmental timing
edad de emplumamiento
feather quality
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