Meeting Abstract
P3.79 Monday, Jan. 6 15:30 Rate of change in metabolic performance in response to thermal variations in three North American passerine species DUBOIS, K.*; HALLOT, F.; MILBERGUE, M.; VEZINA, F.; Université du Québec à Rimouski karinedubois777@yahoo.ca
Thermal acclimatization in birds is associated with adjustments in metabolic performance. Basal metabolic rate (BMR) and maximal thermogenic capacity (Msum, an indicator of cold tolerance) are known to be flexible and studies have reported various amplitudes of adjustments in response to changes in ambient temperature (Ta). However, little is known on the rate of change in metabolic performance in birds subjected to rapid temperature changes and evidences suggest that it may differ between species. We compared three North American passerines species contrasted in their seasonal thermal environment, therefore likely to respond distinctively to the same thermal treatments. Snow buntings (Plectrophenax nivalis, migratory birds found exclusively at northern latitudes), White-throated Sparrows (Zonotrichia albicollis, migratory birds found from southern Canada to southern USA) and Black-capped Chickadees (Poecile atricapillus, resident species experiencing seasonal Ta fluctuations) were first acclimated to 10°C and had their metabolic performance measured (BMR, Msum and MMR, induced by exercise and reflecting stamina). Birds were then separated into “cold” (-5°C) and “warm” (28°C) temperature treatments and performance was measured again on the 4th and 8th day of acclimation (in progress at time of submission). As the extent of temperature fluctuations increases with latitude, we expect Snow buntings and Black-capped Chickadees to express a higher relative rate of acclimation than White-throated Sparrows.
