The home-building habits of the chickadee

My neighbor buddy, Jim, and I were sitting out on my patio one moderately warm March afternoon, drinking pop and talking big, watching the cars go by. We’d wave at the drivers to see if they’d wave back. And we watched the birds coming to the feeders, sometimes buzzing us on their approach.

Jim spotted a chickadee working on a nest hole in my neighbor’s mountain ash tree. The tree is quite a bit the worse for wear, broken off about 15 feet off the ground and getting rather punky. The little bird poked its head in, grabbed some wood bits with its beak, backed out and perched on a nearby branch to clear the sawdust out of its bill.

Another chickadee joined the first one. It went directly to the hole, did some pecking inside, then backed out, perched on a different branch and cleared its beak.

Jim said they must be a pair. He arbitrarily decided which one was the female and imagined what she was telling the male about how the excavation was going. Jim has an active imagination. The chickadees took turns working on the hole for about a half hour and then they were gone.

In my research, I’ve learned that chickadees will often start two or three nest cavities before deciding which one is the best. After all, they have very small bills. They’re not built like a woodpecker, and that’s why they pick dead or dying trees to dig into. They’ll often start their home-building project at a knot hole or where a branch has broken off. They’ll also use a nest hole that another bird has abandoned.

Once the chickadees have gone in a bit, the excavation turns in a downward direction. On the average, the nest cavity will be about 8 inches deep. That means they’ve got to have room to turn around in there. You don’t want to take a chance of bending your tail while you’re backing up.

When they’ve got the cavity just right, the female takes the lead in the nest-building process. The male helps, but the female does the majority of the work. They gather some substantial materials for the base layer, mosses, pine needles, even strips of bark. This base layer can be quite thick, an inch or so. When she gets that to her liking, she begins to add softer, downy material like rabbit fur and cattail fluff.

She takes about a day off before she starts laying eggs, laying an egg a day, usually early in the morning. But she doesn’t start incubating them until she’s only got one egg left. (How does she know?) Whenever she leaves the nest, she covers the eggs with the edges of the downy layer to help conceal them from predators and keep them warm.

By waiting to start incubation until she’s laid all her eggs, she assures that they’ll all hatch at about the same time. In all, she will lay six to eight eggs, dull white with little red dots and streaks on the wide end. They’re less than two-thirds of an inch long and a half-inch wide.

As she sits, incubating her clutch, her mate brings her food. Again, when she leaves the nest, she brings the fluffy layer over the eggs before she leaves. This may also help to make the nest appear empty if some nosy predator peeks in.

Incubation can last 12 or 13 days. As each egg hatches, the adults take the shells out of the nest and some distance from the tree, so there isn’t a telltale pile of shells right under the nest cavity. The female may actually eat the shells to help replace the calcium and minerals expended in producing the eggs.

While the female keeps the newly hatched young ones warm, the male is responsible for bringing food for the whole family. As the nestlings develop their feather coats, they can better regulate their temperature and the female will leave for brief intervals to feed herself and bring back food for the little ones.

But the adults don’t leave the nest “empty-beaked.” They take with them a fecal sac, a convenient container that baby bird poop comes in. They fly off with it, dropping it away from the nest. Sometimes the adults eat the fecal sac, since newly hatched chicks don’t process much of the food they eat, so there’s still quite a bit of nutritional value in what passes through them. And yet they remain so cheerful.

Jim and I hope these chickadees choose “our” tree so we can watch them raise their brood this summer.

 

Clay Christensen lives and writes in Lauderdale. His book, The Birdman of Lauderdale, is available in local bird stores, bookstores and BirdmanBook.com.

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