Meeting Abstract
65.1 Monday, Jan. 6 08:00 Stress and reproduction: What underlies reproductive suppression when birds are brought into captivity? DICKENS, M. J. ; BENTLEY, G. E. *; Univ. of California, Berkeley; Univ. of California, Berkeley m.dickens@berkeley.edu
Intersecting research topics that John Wingfield pioneered, our study aimed to describe mechanisms underlying reproductive suppression in captive wild birds. Male and female European starlings were maintained in outdoor aviaries and sampled for baseline corticosterone (BS) and stress-induced (SI) CORT when birds began to build nests and pair. Half of the birds were then moved to an indoor aviary, while the rest remained outdoors. When outdoor females began to lay (10 days), the experiment concluded and CORT was measured again. Although most indoor females began to nest-build and pair, their ovaries did not progress beyond small white follicles; in contrast, outdoor females exhibited a range of ovarian development and two females laid. Males had no differences in gonad size; however, testosterone was significantly lower in indoor males (0.07+/-0.03ng/mL) compared to outdoor males (1.3+/-0.4ng/mL). Changes in CORT from initial to end samples were significantly different between groups for both BS and integrated SI. This difference appears to be a reduced or lack of change in CORT in the indoor group. BS differences were significantly driven by females (Δng/mL: indoor females=-3.6+/-1.3; outdoor females=9.0+/-2.9; indoor males=3.9+/-3.5; outdoor males=10.1+/-4.9); SI differences were not sex dependent (Δng/mL/min: indoor females=133+/-81.9; outdoor females=441+/-77.6; indoor males= 176.3+/-169.3; outdoor males=382+/-101.2). While higher BS and SI CORT has been demonstrated for breeding birds, our data suggest that this increase can occur within a short time frame (<10 days), associated with the transition to active breeding. In addition, this study suggests that captivity effects may act through suppression of this natural increase in BS and SI CORT.
