Monday, November 21, 2011

Knock-knock...who's there?

An Eastern Phoebe poses on a bamboo cane before attacking its reflection in the window

Simply Living
November 21, 2011

Several years ago, a rufous-sided towhee raged war against the window in my old office. Every day for weeks, the male bird relentlessly attacked the glass with his black, pointy beak.

A couple of years later, a red cardinal engaged in a similar battle. However, unlike the towhee, which focused his testosterone-triggered attention on one particular window, the cardinal made a broader territorial claim. His war involved any surface reflecting his image, including the side-view mirrors on my car.

This year, a new bird has taken up the cause. An Eastern phoebe, a sweet little bird in the flycatcher family, is determined to prove his prowess against the reflection he sees in my current office window.

The Eastern phoebe is a medium-size, brownish-gray bird with white-buff undersides, a black bill, a forked tail and a slightly oversized, darker gray head. One of the phoebe's distinguishing characteristics is the bobbing of its tail feathers up and down, often accompanied by the fluffing of its crown feathers.

Phoebes are wonderful birds to have around homes and gardens because they eat the insects most people find annoying. Ticks, spiders, flies, gnats, mosquitoes, moths, bees and wasps are among the delicacies phoebes enjoy. Bugs are usually caught on the wing, but the phoebe will occasionally pluck an insect off plants or, as I've recently observed, off a window screen.

Distinguishing between the two sexes by physical characteristics alone is difficult with phoebes. Males are slightly larger, and their plumage is somewhat darker, but both of those traits are hard to observe unless the birds are together — and phoebes rarely are. I saw two birds on one occasion, but the rest of the time, I've seen only one. From my observations of that solitary bug-catcher, I've concluded that the bird attacking my window is male — not by the way he looks but by his actions and voice.

Although female phoebes sing, their songs are brief and infrequent. The bird I've observed vocalizes continually. His habit is to perch upon a bamboo pole about three feet away from the window, bob his tail, make some noise, flutter a few inches up into the air, turn around and resettle on the pole, only to repeat the pattern. Intermittently, he attacks the window with his beak, sometimes latching on to the screen with his little claws, spreading his tail feathers and wildly flapping his wings.

The first time that happened, I got scared. I thought the bird was stuck, so I ran outside to help. I needn't have worried. Apparently, the whole body-to-the-window thing was part of his hormonally driven plan to thwart adversaries. As soon as the bird saw me, he easily detached himself from the screen and flew away. I guess the phoebe thought if he waged an all-out, full-body approach, he might succeed at scaring off his reflection. No such luck.

Male birds attack their reflections because of what scientists call "gonadal recrudescence." Testosterone surges during spring mating season and again in autumn. This hormonal flush causes some males to enter defense mode. They deal with any perceived threat to themselves or their mate through posturing, vocalizations and direct body contact.

Such noble but fruitless efforts … such winged flights of fancy.

As much as I love birds, I find the actions of these males baffling. Head-banging against glass seems a step backward on the evolutionary highway.

It's not as if birds are incapable of learning new behaviors. Over time, birds have learned to avoid poisonous or foul-tasting insects. They've learned not to frequent areas that would put them into direct contact with predators. There is even evidence that some birds have learned to avoid newly established and potentially harmful wind turbines. Yet, these flying bits of feather and bone can't overcome the urge to attack their reflection.

The little phoebe at my window is the latest in what will most likely be a stream of avian gladiators, willing to risk their all in defense of their families. Birds may be small — the phoebe weighs less than three quarters — but they are large in determination and devotion to a cause. I just wish their efforts were less painful.

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