Meeting Abstract

P2.134  Tuesday, Jan. 5  The effect of social cues on the timing of the breeding-molt transition in House Finches (Carpodacus mexicanus) BRAZEAL, K. R.*; DECASTRO, D. M.; WATTS, H. E. ; HAHN, T. P.; Univ. of California, Davis; Univ. of California, Davis; Univ. of California, Davis; Univ. of California, Davis krbrazeal@ucdavis.edu

Transitions between annual cycle stages (e.g. breeding, molt, migration, hibernation) allow animals to deal with seasonally predictable and unpredictable environmental variation. Therefore, appropriate timing of these transitions, so that they correspond to optimal environmental conditions, can have a major impact on lifetime reproductive success. Understanding the underlying environmental cue response mechanisms is central to understanding how animals deal with environmental variation. While the responsiveness to photoperiod cues has been widely studied, less is known about how non-photic cues influence the timing of transitions between annual cycle stages. This study examined the importance of social cues in timing of the breeding-molt transition in House Finches (Carpodacus mexicanus). Captive males and females were housed on naturally-declining photoperiod after the summer solstice either adjacent to a hormonally-implanted opposite sex stimulus bird, or to unimplanted same-sex birds. The birds paired with hormone-implanted stimulus companions did not delay gonadal collapse or the onset of molt as predicted. Further analysis of circulating hormone levels and behavioral data may be illuminating. Precisely when in the annual cycle the social cues are experienced may be critical to the response induced.