This tropical bird would rather summer in Westchester County

 ED KANZE PHOTO

By ED KANZE

The bird I’d like to call the “zebra” warbler appears in bird books as the black-and-white. It’s a widespread and often common sight in northeastern forests May through August or thereabouts, and it’s long been one of my favorites. Why do I like it so much? I can’t say with any certainty. I confess a large part of the reason may be that when I was newly converted to birdwatching and hardly knew a hawk from a handsaw, this was among the first birds I learned.

The black-and-white warbler is one of those tropical birds that, for reasons uncertain, has adopted a jet set sort of lifestyle. It spends summers with us. Then, when the weather begins to chill, it follows the stars at night until it reaches wintering grounds in Central America and the West Indies. 

We tend to think of the bird as our bird, one that leaves us for a holiday in the sunshine before coming back in springtime. But the truth is that the black-and-white spends much more of the year in the tropics than it does on its northern breeding grounds.

Why come all the way here from, say, the Bahamas to raise broods of nestlings? Ornithologists don’t know for sure. Without doubt black-and-whites make the long, dangerous journey back and forth to exploit resources more abundant here than at home. One of those resources, perhaps the chief one, is sunshine. In the tropics, days extend only about 12 hours, year-round. During the northern summer, an insect-eating bird that flies to our neck of the woods adds hours to the time it has available for catching insects to feed itself and its offspring. 

In the late 19th century, the black-and-white warbler tended to be called the black-and-white creeping warbler. This is a good name. First, there’s the color scheme. Second, the bird often forages for insects by creeping up and down tree trunks and along limbs. As it moves, it pokes its sharp-pointed bill into crevices in search of insects, insect eggs, pupae, spiders, and whatever else turns up. 

When a male black-and-white sings to woo or reassure a mate or drive off a rival, it opens its bill and squeaks. I’ve heard the sounds compared by birdwatching friends to the squeaking of a gerbil or hamster running on a wheel. 

I tell people that the black-and-white warbler nests on the ground, and eyebrows raise. While plenty of birds nest in trees, sometimes high above the ground, plenty of others nest on terra firma. One of the latter is the black-and-white. 

The nest, built by the female, is made of leaves and plant fibers and is so well-camouflaged it’s challenging to spot. Four or five small white speckled eggs are usually laid. Mother black-and-whites sit on them for 11 or 12 days. Prior to laying, she develops on her bottom a bare patch of skin called a brood patch. This she presses against the eggs, transferring heat. Once the eggs hatch, dad jumps in. Both parents feed and defend nestlings that start out ugly and scrawny and pink and soon develop handsome feathers like their parents.

When insect numbers decline in late summer and tropical migrants such as the black-and-white warbler leave us, they go not in organized flocks or family groups but in a more piecemeal way. We must admire these small, relatively fragile creatures for not only making their long journeys under their own power, but also for doing it without the benefit of maps, GPS, and parental guidance.