Fat reserves in snow buntings

Abstract

Snow buntings (Plectrophenax nivalis) were kept in outdoor and indoor aviaries in Quebec City for 2 years (1970–1972) to study some aspects of their behaviour in winter. Birds kept in isolation or in groups of 2, 4, or 12 individuals were weighed daily at sunset between November and April and once a week during the rest of the year. A very great spring premigratory fattening occurs in early March, relating to the precocity of the spring migration and to the absence of prebreeding molt in this species.Weight changes were related to environmental factors (day length, snow cover, temperature, etc.) over the winter months and to social conditions encountered in captivity. No correlation with current air temperatures was found but day length and snow cover correlated well with weight; however, the relationship was variously modulated by the social surroundings. Poorly identified social factors seemed to play a more important rôle than that played by any single environmental factor selected. Paired birds kept outdoors are considered to represent fairly well the pattern for wild buntings. There was no evidence that social thermoregulation (by huddling) was necessary for this species under Quebec City's winter climate.