To call Kirtland’s warbler endangered is an understatement — save for parts of Wisconsin and Canada, 14 counties in Michigan, especially the region around the Au Sable River between Grayling  and Mio, are the only places in the world where the bird is known to breed today. The world population is estimated at less than 1,400 pairs.
A tiny blue-gray bird with a yellow breast, Kirtland’s warbler winters in the Bahamas, then returns to the Au Sable River area, where it searches for the proper habitat to suit its picky nesting requirements: young stands of jack pine with small grassy clearings. It builds nests on the low-lying branches of jack pines between 5 and 20 feet high; when the trees get much higher, the warbler seeks out younger trees.
The Kirtland’s warbler’s precarious plight is a classic case of habitat loss. When forest fires occur naturally, jack pines are one of the first trees to regenerate in burned areas. But decades of logging and fire suppression led to fewer forest fires, which in turn led to fewer young jack pines. To help the warbler, the U.S. Forest Service, the U.S. Fish and Wildlife Service, and other government agencies now do nature’s job, cultivating, harvesting, and replanting acres of jack pines in the Kirtland’s Warbler Wildlife Management Area, in order to keep an ample supply of young trees suitable for the warbler’s nesting needs.
The Kirtland’s warbler’s breeding grounds are off-limits to the public during the May–August nesting season. From mid-May through June, however, guided tours are led by the U.S. Forest Service (daily, $5) and U.S. Fish and Wildlife Service (daily, free). Of course, actual sightings aren’t guaranteed. For information on the tours, contact the Forest Service’s Mio Ranger Station (989/826-3252) or the Seney National Wildlife Refuge  (906/586-9851).