Meeting Abstract

65.4  Tuesday, Jan. 6  Effects of diet quality on glucocorticoid characteristics in Gouldian finch: lessons for evaluating avian health ASTHEIMER, Lee B*; PRYKE, Sarah R; MAUTE, Kim; GRIFFITH, Simon C; BUTTEMER, William A; University of Wollongong; Macquarie University; University of Wollongong; Macquarie University; University of Wollongong leeba@uow.edu.au

Estrildid grass finches, including the endangered Gouldian finch Erythrura gouldiae, are declining across the extensive tropical savannah habitats of northern Australian. Part of this decline is thought to be related to changing seed quality and availability with changing land use practises. We examined the physiological impacts of low and high quality diets on a captive population of Gouldian finch, including indicators of endocrine, immune function and reproductive function. The diets differed in complexity, seed types and protein content, but were available ad libitum for a 3 month period during which birds underwent moult and mating and attempted breeding. Males and females on the low quality diet exhibited significant reductions in mass, hematocrit, blood hemoglobin level, feather strength and PHA response and these females also had a dramatic reduction in reproductive output. Corticosteroid-binding globulin (CBG) levels in the males and females on the low quality diet were on average half those on the high quality diet, potentially increasing availability of free glucocorticoid. Interestingly, corticosterone levels were not different between females on the two diets, but were significantly lower in males consuming the low quality diet, suggesting the possibility of a gender difference in compensatory response to the increase in free glucocorticoids following a reduction in CBG. These preliminary results will be compared to similar data from free-living populations captured in disturbed and relatively undisturbed habitats.