Question of the week:
How do birds stay warm in the winter?
A. Birds often puff up their feathers when they are at rest on a cold winter's day. The puffed up feathers create larger areas of air that serve as increased insulation.
Some species will also reduce the amount of exposed surface by pulling one leg up into their feathers while tucking their head under a wing.
Many songbird species form communal nests on cold nights. It is not uncommon for a dozen or more Golden-crowned Kinglets, for example, to huddle together in a tree cavity or nest box in order to share body warmth, and up to 60 Pygmy Nuthatches have been found in a single roost cavity.
Nest boxes are sometimes used as a winter roost, and some box designs support adjustable entry hole locations. During the spring the entry hole is near the top. In the winter the entry hole can be placed lower on the box, creating a more effective trap for capturing the body heat of roosting birds.