ProjectThermal tolerance in snow buntings and potential effects of Arctic warming on individual performance
The snow bunting (Plectrophenax nivalis) is a migratory passerine that winters in snowy plains of southern Canada and breeds in the Arctic. As males arrive first on the breeding grounds in mid April, approximately a month before females, these birds experience relatively harsh and cold conditions throughout the year. The species seem well adapted for these environments. However, recent observations suggest that their tolerance to moderate summer heat (~ 25°C), especially when actively flying, might be low. Since the Arctic is warming faster than the rest of the globe, high summer temperatures will occur more frequently. It is expected that theses high temperatures at the time of chick provisioning, where adults are actively flying, might push the birds above their heat tolerance limit. Heat stress could therefore affect individual performance, reproductive success and species distribution. The first objective of this project is to determine thermal tolerance range limits in snow buntings in winter and summer. The second objective is to evaluate the impact of ambient temperature on snow bunting’s effort endurance and individual performance. Different metabolic parameters (cold tolerance, heat tolerance and plumage isolation measures) are measured using respirometry. These parameters will be used to determine the thermal tolerance range limits within which birds are able to keep a normal body temperature. Effort endurance (VO2 max) is also measured by respirometry at different ambient temperatures. This project will allow for establishing original links between temperature, individual performance and reproductive activity in an Arctic warming context.