WANG, S.W.**; KITAISKAIA, E.V.; HATCH, S.A.; IVERSON, S.J.; KITAYSKY, A.S.; Univ. of Fairbanks, Alaska; Univ. of Fairbanks, Alaska; USGS, Alaska Science Center; Dalhousie Univ., Nova Scotia; Univ. of Fairbanks, Alaska: Diet affects the adrenocortical function in northern fulmars (Fulmarus glacialis)

Previous studies have shown that variations in corticosterone secretion in birds might reflect either changes in physiology between different life-history stages or fluctuations in food resources. The objective of this study was to test whether corticosterone secretion in northern fulmars is determined by age, reproductive stage or changes in the diet. We compared baseline and acute stress-induced levels of corticosterone and diets in chicks and adult fulmars breeding on three largest colonies in the North Pacific. We found that corticosterone levels vary inter-annually, among colonies and between incubation and chick-rearing. However, there was no consistency in both inter-annual and inter-seasonal patterns of corticosterone secretion among colonies or between age categories. Qualitative inferences of the diets from fatty acid signature analyses suggest that all differences in corticosterone secretion might be explained by changes in the diet composition. These results suggest that the adrenocortical function of northern fulmars reflect changes in food resources rather than physiological changes in birds among different life-history stages.