Differences mean little to birds in the woods of Saint Martin's Park

N.S. NOKKENTVED

Originally published August 7, 2001

LACEY -- The woods of Saint Martin's Park have become a favorite place for my wife and I to take regular walks.

There are lots of trails through meadows and woods and rarely many people. Deep in the woods the air has that sweet, spicy aroma of the Northwest.

Along the trails we sample blackcaps and thimble berries. Most of the birds we encounter -- from warblers to hawks -- are heard, not seen in the thick forest canopy. But we often see blacktailed deer grazing in openings.

Just before dusk one recent evening, we sighted a bird we had been trying to identify. We had only heard its high-pitched, wheezy call. Then suddenly it appeared on a low branch in a clearing. In the fading light, we didn't get a good look, but it had markings that looked like a black-throated gray warbler.

While trying to get a better look at the little bird, however, a larger bird lit on a branch nearby. At first we thought they were fighting, but then we realized the little warbler was feeding the other bird. We soon identified it as a brown-headed cowbird chick, half again as big as the warbler.

We watched quietly. The naive bird landed on the road a few feet away from us, as if to say hello. It pecked halfheartedly at gravel embedded in the asphalt and flew back up onto a low branch.

The cowbird chick fussed when its surrogate mother arrived with a morsel of food. The forest foster mother made several more trips while we watched. Then, when she flew off again in search of yet another meal for her insatiable charge, the chick followed close behind to thickets deeper in the woods.

Nature's ways sometimes are mysterious.

Cowbirds don't build their own nests. Instead, they lay their eggs in the nests of other birds, sometimes throwing out the eggs of the host bird. The unsuspecting host returns to the nest and hatches out the interloper's chick.

The little warbler -- unwavering in its motherly instinct -- had cared for a strangely large egg that hatched into a voracious baby and unnaturally large and demanding fledgling.

In the end it may not have made a big difference for the individual warbler. It may have been less work to raise a single, though larger, chick instead of the usual four of her own.

For warblers in general, however, it means four fewer baby warblers this year and one more bird that lays its eggs in other birds' nests.

But it is rare for such small warblers to host a parasitic cowbird egg.

The female cowbird apparently isn't judicious in its choice of nests. It is not always successful. Some birds are not capable of raising the parasitic chick, other birds eject the intruder's eggs outright and others simply abandon the violated nest.

More than 150 species unwittingly have raised cowbird chicks, the majority of them songbirds.

We did not see the birds again that evening. But we will return soon to see what else we can learn in Saint Martin's woods.

N.S. Nokkentved covers the outdoors for The Olympian. He would trade his AP Stylebook for the new Sibley Guide to Birds. He can be reached at 360-754-5445.

The Olympian Copyright 2001

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