Testosterone and avian life histories: the effect of experimentally elevated testosterone on corticosterone and body mass in dark-eyed juncos
ED Ketterson, V Nolan Jr, L Wolf, C Ziegenfus… - Hormones and …, 1991 - Elsevier
To assess whether alterations in the normal pattern of testosterone (T) secretion might be
beneficial or detrimental, we studied a breeding population of darkeyed juncos in which we
elevated T experimentally and measured its effect on potential correlates of fitness. We
treated both free-living and captive males with implants that were either empty (C-males,
controls) or packed with T (T-males, experimentals). Timing of implant varied and was
designed to mimic natural peak breeding levels except that peaks were either prolonged or …
beneficial or detrimental, we studied a breeding population of darkeyed juncos in which we
elevated T experimentally and measured its effect on potential correlates of fitness. We
treated both free-living and captive males with implants that were either empty (C-males,
controls) or packed with T (T-males, experimentals). Timing of implant varied and was
designed to mimic natural peak breeding levels except that peaks were either prolonged or …