Natural History Wanderings

Audubon Magazine has an article on how birds survive winter. It describes some of their strategies for keeping warm including:

• shelter in dense foliage or cavities to avoid the elements
• huddle, bunching together to share warmth
• minimize their total surface area by tucking in their head and feet and sticking up their feathers
• puff up into the shape of a little round beach ball to minimize heat loss
• put on fat as both an insulator and energy source
• the ability to keep warm blood circulating near vital organs while allowing extremities to cool down.
• allowing their internal thermostat to drop. Hummingbirds  undergo torpor nightly as their body temperature drops close to outside temperatures

Read more at: How Birds Cope With Cold in Winter | Audubon Magazine.