Meeting Abstract
90.4 Friday, Jan. 7 Lasting impacts of handling on adrenocortical responsiveness of free-living adult and nestling eastern bluebirds LYNN, Sharon E.*; PHILLIPS, Megan M.; PRINCE, Leslie E.; KERN, Michael D. ; College of Wooster; Univ. California, Davis; College of Wooster; College of Wooster slynn@wooster.edu
Field studies often require capture of animals for marking, measuring, and sampling. Capture is a potent stressor that activates the hypothalamo-pituitary-adrenal (HPA) axis. Repeated stressors can alter subsequent HPA responses, impacting an animal’s ability to cope with future challenges. However, little is known about the effects of routine capture or sampling events on subsequent HPA function in wild animals. We investigated this in free-living bluebirds (Sialia sialis). We subjected adults to a capture/restraint protocol and collected blood samples over 60 min of restraint to measure corticosterone (CORT). We administered this protocol to breeding females, either (1) only during brood 1 (Naïve-1), (2) only during brood 2 (Naïve-2), or (3) during both brood 1 and brood 2 (Repeaters). Naïve females had similar CORT responses to restraint; however, for Repeaters, one sampling episode attenuated CORT secretion in response to the same stressor nearly two months later. Since studies of chicks often involve measuring growth, we also investigated whether repeated handling affected HPA response to the capture/restraint protocol in chicks. We used two groups of chicks: manipulated chicks were handled and measured every other day throughout the nestling period, and unmanipulated chicks were not handled prior to sampling. On days 3, 6, 9, and 12 after hatch, we assessed CORT response to the capture/restraint protocol for different chicks from each group. As in adults, manipulated chicks showed attenuated CORT responses compared to unmanipulated chicks. Taken together, our data demonstrate that a small number of handling episodes altered HPA responses to later challenges in free-living birds, and may have important implications for design of field studies in which individuals are repeatedly captured.
