Laura Erickson's For the Birds

Blackburnian Warbler

(Recording of a Blackburnian Warbler)

Every now and then a bird does something so uniquely stupid as to justify the term “bird brain.” Last week an alert Couderay, Wisconsin, listener sent me a clipping from the Chicago Tribune about a Blackburnian Warbler that set out for South America but somehow crossed the Atlantic Ocean instead. This bird, which was probably trying to get to Peru from the Northeastern United States, was apparently swept off course by westerly gales, and made it into the annals of ornithology as the first of its species to be found in Europe–on Fair Isle in Scotland to be precise.

Yes, even with the extraordinary instincts birds have for migration, they occasionally screw up. It’s most likely that the warbler, which weighs only a third of an ounce, didn’t cross the entire 3,000 mile ocean on its own power–it probably hopped a freighter for at least part of the trip. Ocean travel is extremely hazardous for small birds. Not only are they in mortal danger of drowning or starving over the open seas, but also if any gull notices a small bird over water, it calls up its fellow marauders and they drive their victim into the water for a warbler meal. If, against all odds, a warbler does make it safely across the sea, it has more problems than just leaving its travelers’ checks behind. It has to search for the kinds of food it would have found in the tropical rain forest, which aren’t exactly easy to find in Scotland. And once spring comes, it will probably be totally confused about what way to go, and will certainly have trouble finding a mate. When a Bald Eagle accidentally flew to Ireland last year, it was flown back to America by jet, but Blackburnian Warblers don’t have public relations spokesmen to raise their airfare.

The male Blackburnian Warbler is extraordinarily beautiful, with a golden orange head and bib and striking black and white markings. The female is duller, but has a shy prettiness all her own. They breed in northern coniferous forests, especially the kind of untouched mature spruce woods that foresters insist aren’t prime habitat for wildlife. But in Minnesota bog country and in the spruce forests of northern Wisconsin, the Blackburnian Warbler is one of the most common of all breeding birds. Although it’s a bird of the northern forest, it’s also found in the Appalachian Mountains, mainly in oaks and hemlocks.

So if they’re so common, why don’t most people see them? The problem with watching them is that Blackburnian Warblers prefer living at treetop level. They’re so tiny–only 4 1/2 inches long–and so secretive that even John James Audubon himself had trouble finding and recognizing. He painted three different females as “Hemlock Warblers,” apparently never realizing that they were the same species as the male he correctly labeled on only one painting. Another problem with them is that before they light out in fall, the males molt out of their striking colors into dull plumage for their tropical sabbatical. It isn’t much of a vacation. Each individual Blackburnian Warbler joins a mixed flock of birds for a season of searching for food in a diminishing habitat. That lonely bird in Scotland may actually be a pioneer searching for a new place to hang his hat before the tropical forest is gone for good.

(Recording of a Blackburnian Warbler)

This is Laura Erickson, and this program has been “For the Birds.”