Journal Article

Female ornamentation, incubation behavior, and reproductive success in a wild bird

Freeman-Gallant, Corey R., Taff, Conor C.

2021

Overview

In many species, both males and females possess sexual signals, but most research focuses on understanding signal expression in males. Females are often assumed to possess signals as a non-functional by-product of selection on males, but increasing evidence demonstrates functional explanations for variation in female signals. Theory suggests that—for many bird species—differences in long-term fitness associated with female signaling are more likely to be driven by variation in offspring quality than quantity, but research paradigms developed for studying male signals have primarily focused on counting offspring produced. Here, we tested the hypothesis that female ornamentation reliably signals the ability to incubate effectively. We used temperature loggers placed in the nest of common yellowthroat warblers (Geothlypis trichas) to record incubation behavior across multiple breeding attempts. Incubation bout length and the onset of daily activity were highly variable between females, but repeatable within females across multiple nesting attempts. Females with longer bouts and later onset of activity had higher hatching success. Wing length and plumage coloration were not related to incubation length or onset of activity, but were correlated with the total percentage of time spent on the nest each day. However, there was only a trend for repeatability in percentage of time spent on the nest and this measure was not correlated with any metrics of offspring quality or hatching success that we recorded. Therefore, we did not find any single aspect of incubation behavior that was (i) consistent, (ii) related to nestling quality or success, and (iii) signaled by ornamentation. Our results demonstrate the importance of variation in incubation behavior, but also suggest that ornaments are of limited utility as a signal of incubation ability in this species. Nevertheless, our study highlights the need to explore alternative fitness proxies in order to understand variation in female ornamentation.

• Publisher: Springer Science + Business Media,Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Animal breeding / Animal Ecology / Animal reproduction / Animals / Behavior / Behavioral Sciences / Biomedical and Life Sciences / Birds / Breeding of animals / Breeding success / byproducts / color / Coloration / Counting / Females / Fitness / Functional explanations / Gender differences / Geothlypis trichas / Hatching / Incubation / Incubation behavior / Life Sciences / Males / Mate selection / mating behavior / Nesting / nests / Offspring / ORIGINAL ARTICLE / Plumage / progeny / Reproducibility / Reproduction / Reproductive behavior / Reproductive fitness / reproductive success / Signal quality / Signaling / sociobiology / Success / temperature / Time use / Variation / wild birds / Zoology