There are quite a few cavity nesting birds in Michigan but few of them, other than woodpeckers and their kin, are equipped to excavate their own places. Wood Ducks are a classic case in point. They are ducks with duck beaks and not ducks with woodpecker beaks yet they nest in tree holes. Let’s add bluebirds, tree swallows, wrens, kestrels, screech owls and a host of other cavity nesters that are ill-equipped to do woodwork of any kind. All of the above are entirely dependent upon woodpeckers, rot, gnashing squirrels, and handy humans to produce their hollow homes.
Chickadees are cavity nesters as well, but they do not belong on the previous list of unsuitable carpenters. It is a surprising fact of nature that these tiny dynamos can – and often do – excavate their own nest holes. They have tiny beaks suited for insect grabbing and this appears to be a major evolutionary problem. After-all, wood excavators need powerful chisel-like beaks and re-enforced skulls in order to do their job and stay healthy while doing it. Sending a Chickadee out to do this type of work would be like putting the kicker in as a linebacker against 300 pound opponents. It would all be over in seconds with a flattened kicker, or a smash-faced chickadee, on the field.
Somehow, chickadees seem to manage the impossible. Actually they have found a way to get around the impossible (letting the 300 pounder motor past and tripping him up, you could say). I recently watched a pair of these black and white birds working on a nest cavity and found myself admiring the process (watch short movie here). Their chosen site was a Hawthorn stub broken off about six feet from the ground. The snag itself was partially rotten – which is key to this type of Chickadee peck-work. These birds can’t possibly chip away at hard wood but can make do with firm rotten wood.
They were working a spot about 6 inches from the top and had opened up an entrance about 1 inch in diameter by the time I came upon the scene. A brief check of the literature (I don’t like to make everything up!) revealed that most Black-capped Chickadee holes are located within 10 inches of the stub tip. I would assume that this is the place where the wood is punkiest, so it makes sense in that regard. Oddly enough, these birds don’t show any preference for orientation – they place the hole where ever it is easiest to make. Yes, I read that also.
Taking turns, each bird worked the hole for about 5 minutes before yielding to their mate. The improbable woodpeckers flew down to the hole, braced themselves with a wide stance, and then directed measured blows at the wood. Their action was like that of an ice pick – repetitive but not spastic. Wood chips were mostly tossed to the side and larger chunks were carried off. The act of carrying off one of these larger pieces appeared to be the signal for the other bird to come forward.
In between sessions the birds sat around for a minute, as if shaking off a headache (see above), before starting to seek food. Once, when one of the birds returned to work, he (or she?) started on the wrong location – the actual end of the stub – and pecked at if for a half-dozen blows before realizing its mistake and dropping down to the correct hole.
I do believe I was witness to a case of Chickadee fatigue in that case. The chickadees stopped soon after this incident and left after 20 minutes of hard work. Their labors resulted in a cavity with the entrance defined and an internal space of only about ¾ of an inch. It was a good start, but only a start. Being so ill-equipped for the job they will spread the labor out over an extended period of time. This is about the only thing that these animated birds do that can be considered slow. The job will get done but it will be on Chickadee time.