Laura Erickson's For the Birds

Black-capped Chickadee

(Recording of a Black-capped Chickadee)

Winter in the frigid Northland can seem like an endless ordeal to a displaced southerner, especially when it begins as early as it did this year, but to offset the season’s bitterness, to brighten even the worst blizzard, we have the chickadee.

(Recording of a Black-capped Chickadee)

The Black-capped Chickadee is little more than fluff and fire. It weighs only a third of an ounce–you could mail three of them with a single postage stamp. But, encased in its warm down coat and cap, the chickadee is perfectly adapted to the worst Minnesota winter. Its body is shaped about as sperically as a bird can get, to reduce its surface area and conserve heat. Its tail feathers are long, but feathers are like human hair–they don’t have any circulation and so don’t lose heat. The feet and legs on all perching birds contain no fleshy muscles at all–only tough tendons with a limited vascular supply. The temperature of the feet can drop to near freezing, and the blood flow can be shut off just about completely, when the air temperature is low. If a chickadee loses a toe on a cold day, it probably won’t bleed–it may not even feel it. The feet of perching birds have a very small nerve supply–so few nerves that Gray Jays have perched without apparent discomfort for almost a full minute on a hot camp stove.

Chickadees join winter feeding flocks in fall, and move around together through a winter territory. It’s easy to attract them to your window. They’re fond of sunflower seeds, suet, cracked walnuts, peanut butter, and cracked corn. Their eating method seems very inefficient– they snatch a single seed or bite of suet and fly off to eat it in a tree or shrub. They peck at a sunflower seed several times before they get the shell off, quickly eat the seed, and then return to the feeder just to grab another seed and fly off again. It seems like the work involved must exceed the amount of energy they get from the meal, but, then again, it’s hard to imagine how anything as busy as a chickadee could possibly be energized no matter how it ate. When sound asleep, a chickadee’s heart beats 400 times a minute–when active or excited, this rate is doubled. It even blinks over 40 times every minute.

In spite of its adaptations to the cold and its apparent liveliness, the chickadee has a life expectancy measured in months, not years. Each pair lays 6-8 eggs every year, but the total number of chickadees stays pretty much the same from one year to the next. House cats, Sharp-shinned Hawks, and other predators take a heavy toll. Raccoons can easily reach into a chickadee roost in a tree cavity at night and pick off a whole flock. A chickadee probably mates for life, but will take a new mate if its mate dies–females have been recorded replacing their mate three times in a single season. But if a chickadee does survive its first year, its life expectancy goes up sharply–one banded bird lived for over 12 and a half years and several have lived for over nine years, cheering Northlanders in the dreariest of winters.

(Recording of a Black-capped Chickadee)

This is Laura Erickson, and this program has been “For the Birds.”