Meeting Abstract

47.1  Jan. 6  Chronic stress and corticosterone: CORT response to seven days of rotating stressors in two free-living songbirds BUTLER, L K*; HAYDEN, T J; BISSON, I; WIKELSKI, M; ROMERO, L M; Tufts University, Medford, MA; US Army Engineer Research and Development Center, Champaign, IL; Princeton University, Princeton, NJ; Princeton University, Princeton, NJ; Tufts University, Medford, MA luke.butler@tufts.edu

Vertebrates require time and energy to cope with and survive prolonged disruptions of the life cycle, or �chronic stress� (after Wingfield 2005, J. Mamm.). Therefore, distinguishing chronically-stressed from non-chronically-stressed populations is important for species conservation. Recently, chronically-stressed captive European Starlings were shown to have lower basal and acute stress-response levels of corticosterone (CORT), the major avian glucocorticoid, than non-chronically-stressed starlings (Rich and Romero 2005). We studied the effect of chronic stress on CORT levels in free-living populations of an endangered songbird, the Black-capped Vireo, and a non-endangered, sympatric congener, the White-eyed Vireo. For each species, we attempted to create a group of chronically-stressed adults by presenting rotating, unpredictable stressors at nests during the incubation and nestling stages. After at least 7 days of stress treatment, we captured adults and sampled basal and acute stress-response CORT concentrations, which we compared to non-chronically stressed adults at the same stage of the breeding cycle. Our results 1) illustrate any effect of chronic stress on CORT levels in two free-living songbirds, 2) compare the CORT response to acute and chronic stress between an endangered species and a common, sympatric congener, and 3) demonstrate the utility of CORT comparisons for identifying chronically-stressed vertebrate populations.