Hormones in the city: Endocrine ecology of urban birds

Urbanization dramatically changes the landscape, presenting organisms with novel challenges and often leading to reduced species diversity. Urban ecologists have documented numerous biotic and abiotic consequences of urbanization, such as altered climate, species interactions, and community composition, but we lack an understanding of the mechanisms underlying organisms' responses to urbanization. Here, I review findings from the nascent field of study of the endocrine ecology of urban birds. Thus far, no clear or consistent patterns have been revealed, but we do have evidence that urban habitat can shape endocrine traits, and that those traits might contribute to adaptation to the urban environment. I suggest strong approaches for future work addressing exciting questions about the role of endocrine traits in mediating responses to urbanization within species across the globe.

► Urban habitat presents novel challenges to organisms all across the globe.
► This review describes findings of studies of the endocrine ecology of urban birds.
► Numerous endocrine effects associated with urban habitat have been described.
► However, clear, consistent patterns have not yet been revealed.
► With more rigorous approaches, future work will provide important advances.