Meeting Abstract

67.5  Thursday, Jan. 6  Short-term adjustments of metabolic performance in wintering black-capped chickadees: is phenotypic flexibility fast enough to cope with daily climatic variations? PETIT, M.*; LEWDEN, A.; VEZINA, F.; Université du Québec à Rimouski, Canada; Université du Québec à Rimouski, Canada; Université du Québec à Rimouski, Canada Magali.Petit@uqar.qc.ca

Small resident bird species wintering at northern latitudes face harsh ecological conditions on a daily basis and must adjust their physiology to improve their chances of survival. Winter acclimatization in these birds is associated with several physiological adjustments such as an increase in basal metabolic rate (BMR) and thermogenic capacity (summit metabolic rate: Msum). However, studies on seasonal acclimatization typically compare birds caught once in summer with individuals caught once in winter. Little is known about short-term phenotypic adjustments to natural winter climatic variations. Phenotypic flexibility could allow a bird to rapidly adjust its performance to prevailing conditions. Alternatively, phenotypic flexibility could be too slow to track short-term climatic variations, therefore leading to periodic mismatches between a bird’s physiological performance and ecological requirements. Using black-capped chickadees (Poecile atricapillus) as our model species, we investigated how short-term climate variability affects metabolic performance in small wintering passerines. Metabolic performance was assessed on a daily basis between December 2009 and April 2010 by measuring BMR and Msum on up to four bird per day. Metabolic performance was then interpreted in light of daily climatic variations (temperature, wind speed, relative humidity, solar radiation and snow cover) measured by automated weather stations. Preliminary results suggest a steady decline in BMR over the winter, independent of weather conditions.