During the winter, many creatures are able to drastically decrease their body temperatures and energy use and enter a reduced state of metabolism. Even though environmental temperatures may be well below freezing, these animals survive. This is due in part to their hibernation but most importantly to the fact that

Athey are covered with feathers.

Bwater has a high specific heat capacity.

Cthe ion concentration within their cells increases.

Dthey pick a location that allows them to avoid freezing.