Patterns of Testosterone In Three Nearctic-Neotropical Migratory Songbirds During Spring Passage

Document Type

Article

Publication Date

12-1-2015

Department

Biological Sciences

School

Biological, Environmental, and Earth Sciences

Abstract

Preparation for breeding may overlap extensively with vernal migration in long-distance migratory songbirds. Testosterone plays a central role in mediating this transition into breeding condition by facilitating changes to physiology and behavior. While changes in testosterone levels are well studied in captive migrants, these changes are less well known in free-living birds. We examined testosterone levels in free-living Nearctic-Neotropical migrants of three species during their vernal migration. Testosterone levels increased during the migratory period in males of all three species but significantly so in only two. Testosterone levels in females remained the same throughout their migration. Our results support the extensive overlap between vernal migration and breeding preparation in male songbirds. The pattern of testosterone changes during vernal migration is far from clear in females.

Publication Title

General and Comparative Endocrinology

Volume

224

First Page

186

Last Page

193

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