Des Ursulines Building
300 Allée des Ursulines
Winter is a challenging period for small birds of the northern temperate zones. Colder temperatures force birds to increase energy expenditure for thermoregulation and severe weather conditions can reduce the availability of food resources. In order to survive these energetic constraints, birds must adjust their behavior, physiology or both. The snow bunting is an Arctic-breeding migratory songbird wintering in the central latitudes of North America, spending the majority of its annual cycle in relatively cold areas. This species appears to be well adapted to survive in harsh winter conditions but little is known on its winter behavior and physiology. My project therefore aims at gaining a better understanding of two facets of snow bunting’s winter ecology, namely 1) winter fattening and 2) nomadic movements. 1) Many resident passerines are known to increase lipid storage as mid-winter approaches. Fat reserves accumulated during the day act as the primary source of energy to survive the night ahead and offer a safety margin against starvation in case access to food becomes restricted. Like many resident songbirds, snow bunting’s winter acclimatization involves a seasonal increase in energy reserves, yet the mechanisms that regulate this pattern are not well understood. The first objective of my project is to identify the environmental factors driving winter fattening in snow buntings. Using a winter banding dataset from eastern Canada in combination with weather data, I will identify which environmental variables are the most influential on the seasonal variation of body weight and fat stores in this species. 2) While snow buntings have a certain capacity to cope with winter severity by augmenting fat depots, recaptures of banded individuals also show that birds can migrate away from bad conditions, sometimes traveling hundreds of kilometers in a single season. Yet the environmental cues prompting birds to engage in such large-scale movements are unknown. The second objective of my project is to determine the influence of weather on bird’s winter nomadic migratory movements. Banding and meteorological data will be examined in order to see if flock structure changes in response to local climate fluctuations during winter. More specifically, I will determine whether temperatures constraints and individual’s cold tolerance act as a driver of movements. According to a long-term winter survey (Christmas Bird Count), North American snow bunting populations would have undergone a 64% decline over the past 40 years. This project will allow a better understanding of the wintering behavior and seasonal acclimatization strategies of this songbird and, ultimately, help identifying the mechanisms behind the potential decline that the species has been experiencing.