Nature’s Notes: Adaptions help chickadees survive the cold

Black capped chickadees are one of the most common birds to visit backyard feeders. They seem to be common everywhere and especially enjoy eating sunflower seeds, peanuts, and suet. Chickadees are early risers, often visiting feeders at dawn. Small feeders swinging in the wind don't bother them but unlike woodpeckers and cardinals they rarely tarry. Typically a chickadee lands, quickly snatches a seed, and immediately zooms off.

Six chickadee species live in North America but Iowa's is the black capped. It ranges from the Atlantic coast across the continent to interior Alaska. Unlike many birds it doesn't migrate and spends the entire year in the same general area.

An adult chickadee weighs but four-tenths of an ounce and must ravenously eat to maintain its daytime body temperature of 108 degrees. That's challenging enough in frigid Iowa, but an Alaskan chickadee has only a few hours of daylight to forage before settling in for a 20 hour long subzero night.

This amazing bird has many adaptations that help it survive. It tends to molt in late summer, discarding old worn feathers and replacing them with new heavier ones that are one of nature's best insulators. At dusk a chickadee tucks itself into a tiny crevice that helps hold body heat. The sleeping bird lowers its body temperature to about 85 degrees, saving precious energy.

During warm months chickadees mostly feed on insects and spiders but when the world freezes up their diet is cosmopolitan. In addition to seeds they dine on frozen insects, peck at the bodies of dead animals, and even eat pieces of icicles of frozen maple sap that drips from trees in late winter.

The cheerful energy of this tiny bird as it grabs seed from a window feeder brings winter joy to humans who love watching chickadees.

An outstanding website for free information on hundreds of bird species check out the Cornell University Laboratory of Ornithology at www.birds.cornell.edu.