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Dehydroepiandrosterone in songbird plasma: seasonal regulation and relationship to territorial aggression
1Department of Zoology, University of Washington, Seattle, Washington 98195-1800, USA. kiran@physci.ucla.edu
Abstract:
Many male animals are territorial in the breeding season, when plasma testosterone (T) levels are high, and nonterritorial in the nonbreeding season, when plasma T levels are basal. In contrast to this common pattern, male song sparrows (Melospiza melodia morphna) are territorial year-round, except briefly during molt. Song sparrows are highly aggressive in the nonbreeding season (autumn and winter), even though plasma T, 5 alpha-dihydrotestosterone, androstenedione (AE), and 17beta-estradiol levels are undetectable (
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