Breeding cycles and fecal gonadal steroids in the brown dipper Cinclus pallasii.
Breeding cycles and fecal gonadal steroids were investigated in free-living brown dippers, Cinclus pallasii. The brown dippers were marked with colored leg bands, and their behavior was observed by a field scope. The breeding season was divided into six stages according to the behavior observed; winter territory-defending, nest-building, copulation, incubation, nestling, and fledgling stages. Fecal pellets on the stones in their territories were collected and the levels of immunoreactive estradiol-17 beta (E2) and testosterone (T) in 10 mg feces were measured by radioimmunoassay. Levels of fecal E2 were high only during the copulation stage, which lasted for a few weeks, in all females of the three pairs observed. In contrast, T levels in the feces of males increased in late winter when intensive territory-defending behavior was observed, and remained high until the end of the breeding season. T levels during the nest-building stage and the copulation stage were similar to those during other nesting stages. When the birds breed only once a year, the duration of high levels of T was shorter than that of the pair with the second clutch. T levels in the feces of females showed a similar pattern to E2 levels.
Kofuji
H
H
Department of Biology, Nara Women's University, Japan.
Kanda
M
M
Oishi
T
T
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001717:Birds / Q000502:physiology*; D003307:Copulation; D004958:Estradiol / Q000032:analysis*; D005243:Feces / Q000737:chemistry*; D005260:Female; D008297:Male; D009425:Nesting Behavior; D012098:Reproduction / Q000502:physiology*; D012621:Seasons; D012727:Sex Characteristics; D013731:Territoriality; D013739:Testosterone / Q000032:analysis*
D013739:Testosterone; D004958:Estradiol