title: Patterns of testosterone in three Nearctic-Neotropical migratory songbirds during spring passage.
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.
authors: Department of Biological Sciences, University of Southern Mississippi, 118 College Drive Box 5018, Hattiesburg, MS 39406, USA; Shoals Marine Laboratory, 102 Chase Ocean Engineering Lab, 24 Colovos Rd, Durham, NH 03824, USA. Electronic address: kristen.covino@eagles.usm.edu.
authors: Kristen M
authors: KM
authors: Covino
authors: Shoals Marine Laboratory, 102 Chase Ocean Engineering Lab, 24 Colovos Rd, Durham, NH 03824, USA; Biology Department, Canisius College, 2001 Main St., Buffalo, NY 14208, USA.
authors: Sara R
authors: SR
authors: Morris
authors: Department of Biological Sciences, University of Southern Mississippi, 118 College Drive Box 5018, Hattiesburg, MS 39406, USA.
authors: Frank R
authors: FR
authors: Moore
mesh_terms: D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D001947:Breeding; D005260:Female; D008297:Male; D012621:Seasons; D020308:Songbirds / Q000502:physiology*; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone
keywords: Annual cycle; Birds; Breeding preparation; Migration; Testosterone