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Developmental changes in serum androgen levels of Eastern Screech-Owls (Megascops asio)

January 1, 2010

We studied androgen production during development in nestling Eastern Screech-Owls (Megascops asio) and hypothesized that gender and hatch order might influence serum levels of testosterone and androstenedione. Testosterone levels were highest immediately after hatching and declined significantly in the 4 weeks leading to fledging. The average level of testosterone for 1-7 day-old owls was 3.99 - 0.68 ng/ml. At 22-28 days of age, the average testosterone level for nestling owls was 0.83 - 0.18 ng/ml. Testosterone levels did not differ between males or females. The average testosterone level for male nestlings was 2.23 - 0.29 ng/ml and 2.39 - 0.56 ng/ml for female nestlings. The average level of androstenedione for nestling owls was 1.92 - 0.11 ng/ml and levels remained constant throughout development. Levels were significantly higher in males than females. The average androstenedione level was 1.77 - 0.16 ng/ml for male nestlings and 1.05 - 0.24 ng/ml for female nestlings. Hatching order did not affect levels of either androgen. Our results provide a foundation for future studies of androgen production by nestling owls.

Publication Year 2010
Title Developmental changes in serum androgen levels of Eastern Screech-Owls (Megascops asio)
Authors Corinne P. Kozlowski, D. Caldwell Hahn
Publication Type Article
Publication Subtype Journal Article
Series Title Wilson Journal of Ornithology
Index ID 70003571
Record Source USGS Publications Warehouse
USGS Organization Patuxent Wildlife Research Center