Winter food supply and avian energetics

Winters in temperate regions can be challenging for small birds. Short days, long cold nights and reduced food supply mean that it is especially important to feed as much as possible during the day to store sufficient energy to survive the night. Small birds routinely reduce their body temperature at night, becoming hypothermic, to conserve energy and increase their chance of surviving the night. Access to a reliable and energy-rich food supply is presumably important in determining a bird's energetic status and the extent to which they need to reduce their body temperature at night. In this project, we manipulated winter food availability in the wild for great tits and studied the effects on body temperature regulation, metabolic rate and the ability to fight an infection. We also investigated the carry-over effects of winter feeding to the breeding season.