P2.173 Thursday, Jan. 5 Three weeks of daily, randomized exposure to rain, cold and food restriction do not elicit symptoms of chronic stress in molting European starlings DE BRUIJN, R; MERULLO, D*; WANG, L; CASH, J; ROMERO, LM; Tufts University email@example.com
Repeated exposure to noxious stimuli causes chronic stress in animals, which is thought to reduce the ability of the animal to respond to additional stressors and potentially hampers survival. However molting birds appear to respond differently to chronic exposure to stressors. This study investigated heart rate and corticosterone responses of eight molting European starlings (Sturnus vulgaris) in response to a three week protocol, during which animals were exposed to 30 minutes of artificial rain or cold and a two hour food restriction period every day. Each of these stimuli elicits an acute stress response in the laboratory. Such weather related stressors are thought to be more relevant to molting birds, due to a higher protein demand and potentially less effective insulation as feathers are replaced. The order and application times of the stressors were randomized to prevent habituation and animals were exposed to three or four stressors per day. Weight increased from baseline throughout the chronic stress period, reducing back to baseline during the recovery period. No changes in daytime or nighttime basal heart rate were found before, during and after the chronic stress period. Birds responded to a standardized stressor with an increase in heart rate, which was the same throughout the experiment. No changes in baseline or stress-induced corticosterone levels were found. Neither corticosterone negative feedback nor maximum adrenal capacity changed over the course of the experiment. In conclusion, weather related stressors do not appear to cause chronic stress in molting European starlings.