Meeting Abstract
One expected consequences of climate change, in addition to extreme climatic events, is increased short-term variation in ambient temperature. Although avian thermal adaptations have been studied for decades, we have limited knowledge of the physiological responses of birds to rapid changes in Ta. Using species contrasted by their natural thermal environments (black-capped chickadees, white throated sparrows and snow buntings), we tested whether and how components of metabolic performance (basal and summit metabolic rates, BMR and Msum respectively) responded to a rapid (<24h) 15-18°C change in Ta. In a parallel experiment, we investigated how the rate and amplitude of metabolic flexibility were affected by previous regimes of temperature oscillations in zebra finches. In wild species, we found that both BMR and Msum can change significantly within 8 days following a change in temperature but that these parameters respond at different rates, likely reflecting changes in different physiological body components. We also found that metabolic performance may take 1-4 weeks to reach a new stable phenotype in zebra finches and that the amplitude of phenotypic differences between acclimation temperatures (7 and 35°C) is twice as large in birds that experienced previous temperature oscillations relative to those that were maintained in a stable thermal environment.
