Are corticosterone levels a good indicator of FOOD STRESS AND reproductive success in a seabird colony?
Richard B. Lanctot*1, Scott A. Hatch1, Verena A. Gill1, and Marcel Eens2 1USGS-BRD, Alaska Biological Science Center, 1011 E. Tudor Road, MS 701, Anchorage, Alaska 99503 USA, Richard_lanctot@usgs.gov ; 2 Department of Biology, University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium. To determine if stress hormone levels in adult seabirds are related to local food conditions and indicate the reproductive health of a colony, we contrasted base-line levels of corticosterone in supplementally fed and unfed adult Black-legged Kittiwakes (Rissa tridactyla) breeding on a radar tower on Middleton Island, AK in 1999 and 2000. Blood was obtained from adults shortly after returning from the wintering grounds (~1 months prior to breeding), and during pre-egg laying, incubation and chick-rearing stages of breeding. A variety of reproductive parameters were also measured at fed and unfed sites throughout the colony. Base-line levels of corticosterone were 2-3 times higher in birds sampled
