Meeting Abstract

47.7  Jan. 6  Hormone-behavior correlations vary with energetic stress in breeding male tree swallows (Tachycineta bicolor) CZARNOWSKI, M.R.*; LOMBARDO, M.P.; POWER, H.W.; Rutgers University; Grand Valley State University; Rutgers University czar@wildbehavior.net

We previously demonstrated that clipping the primary wing feathers of breeding male tree swallows (Tachycineta bicolor) decreased certain parental care behaviors such as nestling feeding rate. Contrary to expectation, however, we did not find treatment group to affect hormonal stress response or immunocompetence. This current analysis examines the way physiology interacts with our manipulation in predicting behavioral variation during the breeding season. Our findings suggest that clipping changed the way in which internal physiology relates to observed behaviors. For example, control birds displayed a significant positive correlation between humoral immunocompetence and feeding rate (Spearman rho= 0.636, p<0.05), while birds with clipped feathers showed no correlation (Spearman rho=.002, p=.9953). Immune response therefore appears to be an accurate predictor of nestling provisioning for relatively unstressed birds, but not for birds experiencing high levels of energetic stress. This experiment, therefore, highlights the limitations of physiological correlations with behavior, and stresses the need to take external factors into account when attempting to predict future behaviors.