UC Davis

Abstract : As an important determinant of reproductive success, avian nest building is under strong selection and requires behavioral plasticity to optimize conditions in which offspring develop. Learning is a one form of plasticity that allows adaptation to the local environment. Birds may refine nest-building behavior with personal experience or use social information to guide their choices. While there is mounting evidence for an effect of experience-based learning on nest building and social information use when selecting nesting material in the laboratory, experimental evidence for social information use in wild birds is lacking. Here, we provided sources of two differently colored wool as nest lining material in a wild mixed-species community of tits (Paridae sp.) to investigate experimentally (i) whether females use social information to locate lining materials and (ii) whether preferences for specific materials (here color) are socially influenced. We investigated pathways of social transmission through a foraging association and a spatial breeding network using the time of arrival at the wool in a network-based diffusion analysis. Our results gave evidence that birds learned about the location of lining resources from foraging associates. Furthermore, we found significant non-random clustering of wool colors in nest boxes across the study area, suggestive of a social influence on selecting lining materials. Taken together, we provide quantitative evidence for a role of social information use in both finding and selecting lining material in wild tits and demonstrate that social information use constitutes an important factor towards behavioral plasticity in nest building in wild birds. Significance statement: As vessels of reproduction, avian nests are under strong selection to provide optimized conditions for developing offspring. Learning is one mechanism that allows individuals to adapt to local environmental conditions. Previous work has shown that nest-building birds use both social information and personal experience to refine their nests. Yet, evidence for social information use for nest construction in the wild has been purely anecdotal and experimental evidence lacking. Here, we demonstrate for the first time experimentally that in wild tits (Paridae sp.), females rely on social information from their foraging associates to locate and choose material to line their nests. This research highlights the importance of social information use as a potential mechanism of behavioral plasticity in wild nest-building birds.