The Secret Life of the Kirtland’s Warbler
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BBXR (Blue, Blue, Metal, Red)-banded
Kirtland's Warbler
© Dave Currie
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By Chuck Hagner
Photographs by Layne Kennedy
Show me a warbler, and I’ll show you a feathered sprite, a half-ounce dynamo.
Show me a warbler that migrates over open seas, and I’ll show you a marvel, a species that ornithologists want to know more about.
But show me an endangered warbler that breeds only in Michigan and winters only in the Bahamas, and I’ll show you an avian celebrity complete with a fan club of bird-watchers, scientists and conservationists aching to know more about the creature’s private life.
I’ll show you a Kirtland’s warbler.
But only if I can find one.
The bluish gray, black and lemon-yellow warbler is famous for a confiding, almost tame, manner and a penchant for singing loudly from conspicuous perches in young jack pine trees each spring. But finding it on its winter grounds in the Bahamas is a different story. For most of the last century, searches for the bird outside of breeding season have been close to exercises in futility.
Since the first specimen was collected on the island of Andros in 1879, only about 200 individuals have been spotted in the Bahamas, and never a flock. The birds were usually stumbled upon by chance and seen only briefly. Even more discouraging, they weren’t found on any one island but scattered throughout the Bahamas, a 625-mile-long archipelago that stretches across approximately 100,000 square miles of the Atlantic.
I mounted my own search for the warbler in March 2005, traveling to Eleuthera to visit the Kirtland’s Warbler Research and Training Project—a cooperative effort of The Nature Conservancy, the U.S. Forest Service, the Bahamian government, the Bahamas National Trust and the College of the Bahamas. Project participants not only had found wintering Kirtland’s warblers but also were unlocking secrets of the bird’s life story.
My flight from Nassau to Eleuthera took only half an hour, barely enough time to recollect the names of all the people whose searches had laid the groundwork for the project’s success. They included collectors, renowned ornithologists, conservationists, experts on the Kirtland’s warbler, even a man who lent his name to a well-known fictional secret agent. The real James Bond was a curator at Philadelphia’s Academy of Natural Sciences for 50 years and an expert on the birds of the West Indies. He spent about 100 days looking for the warbler in the late 1930s and found only one. Harold Mayfield, the Ohio ornithologist who wrote a definitive monograph on the warbler in 1960, was another searcher. He and Josselyn Van Tyne, curator of birds at the Museum of Zoology at the University of Michigan and one of the first to band the Kirtland’s, spent five weeks in 1949 looking on the islands of New Providence and Eleuthera. They found none. Wisconsin ornithologist John T. Emlen Jr. searched, too. He spent 500 hours combing measured tracts on Grand Bahama and Andros islands from 1968 to 1971. He came across only a single Kirtland’s. “Unless the birds are concentrated in some locality or in some unusual habitat not yet discovered,” Mayfield wrote in 1972, “the prospect of finding them is discouraging indeed.”
In the last part of the 20th century, the Kirtland’s warbler appeared to be a species on the brink of extinction. In 1974 and again in 1987, trained observers in Michigan counted only 167 singing males. State and federal agencies poured millions of dollars into creating and maintaining the conditions the bird requires for successful nesting. Decades later, their efforts appear to be succeeding: The June 2005 census yielded 1,415 singing males, the most ever. But are the Michigan efforts wholly responsible for the bird’s recovery? We don’t know. Events that occur after the warbler leaves its breeding grounds have to play a role in determining how many birds return to sing again the following spring. But which events? And how big a role? Scientists just haven’t been able to say.
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