The black-capped chickadee is a familiar sight in winter landscapes. Its short, stout bill, dark head cap and white cheeks give it a unique appearance. It also has a unique call, which can sound like a squeak or a chatter, and is encoded with information about the bird’s surroundings.
While other birds can escape frigid winter weather by flying south, chickadees have a more pragmatic approach: they can drop their body temperature at night, which protects them from freezing. But to do this, the chickadee must generate a lot of heat during the day and spike its metabolic rate. Then it must conserve that energy by minimizing heat loss at night.
During the winter, black-capped chickadees can lower their core temperatures up to 25 degrees Fahrenheit below normal. That’s a remarkable feat, especially for a little bird that weighs only 10-12 grams. The birds’ feathers also provide insulation: Their down feathers trap a layer of insulating warm air next to their skin; the outer feathers form an oily, water-resistant shield against wind and moisture.
On the coldest nights, the chickadee can even go into regulated hypothermia, slowing its metabolism and lowering its heart rate to conserve as much of its reserve energy as possible. And then there’s its fat, which can hold in more warmth than the feathers.
All this makes the chickadee a very special creature indeed, which is probably why it has become one of the best-selling hardcover children’s books in northern Michigan this year, according to Horizon Books in Traverse City. The book, Chickadees at Night, by Empire author Bill O’Smith and illustrated by Traverse City watercolorist Charles R. Murphy, is not a fact book; rather it’s a flight of fancy into the mysteries of nature.