Meeting Abstract

90.3  Friday, Jan. 7  Unpredictable Food Availability as an Ethologically Relevant Chronic Stressor in European Starlings (Sturnus vulgaris) BAUER, C.B.*; GLASSMAN, L.G.; ROMERO, L.M.; Tufts University; Tufts University; Tufts University carolyn.bauer@tufts.edu

Both the fight-or-flight and hypothalamic-pituitary-adrenal (HPA) axis responses have been well studied in chronically stressed European starlings. In this study we attempted to characterize the heart rate and corticosterone (CORT) responses in European starlings via an ethologically relevant chronic stressor: food availability. Food was available ad libitum for the first 7 days of the experiment (Control period) and then birds were split into two groups, which were food deprived for 4 hours each day at either i) the same time of day or ii) an unpredictable time of day for 20 days (Food Restriction period). Birds were then given food ad libitum for a 15-day Recovery period. In addition to measuring heart rate, baseline CORT, and stress-induced CORT levels, we also collected food consumption and behavior data. All birds significantly increased in weight during the Food Restriction period and remained above their original weight during the entire Recovery period. We found that both groups of birds ate more food per day during both the Food Restriction and Recovery periods. While daytime baseline heart rate did not change over the experiment, all birds showed a decrease in heart rate when food was removed from the cage during the Food Restriction period. We saw no differences in either baseline or stress induced CORT over the course of the experiment. These data suggest that unpredictable food availability alters the fight-or-flight response and eating behavior, but does not have a long-term impact on the HPA axis.