By Cate Harrington

Dave Ewert, Conservancy senior conservation scientist, has studied Kirtland’s warblers for more than 20 years. This tiny migratory warbler, at the brink of extinction in the mid-1980s, has rebounded to more than 1,800 pairs today thanks to successful efforts to develop and maintain its nesting habitat.

Nature.org: Why is this bird so rare?

Dave Ewert: Kirtland’s warbler populations were probably never large. The bird breeds in large stands of young jack pine forests, primarily located in a few northern Michigan counties, which were historically maintained by fire. When fire was suppressed during the 20^th century, young jack pine stands were lost. Habitat loss, combined with parasitism by the brown-headed cowbird, which lays its eggs in other birds’ nests, resulted in very low numbers of Kirtland’s warblers by the mid- to late 1900s.

Nature.org: Does this warbler occur in Wisconsin?

Dave Ewert: Singing males have been seen in Wisconsin in the past, but the first documentation of nesting did not occur until 2007, when nests were found at one site in central Wisconsin.

Nature.org: Where do Kirtland’s go in the winter?

Dave Ewert: Their wintering grounds were a mystery until 1879, when one bird was found on the island of Andros in The Bahamas. But The Bahamas encompasses more than 700 islands, a large area in which to search for a bird that skulks around in dense underbrush. Finally, in 2002, six Kirtland’s warblers were spotted on the island of Eleuthera by the ornithology group of the Bahamas National Trust, opening the door to studying their winter ecology.

Nature.org: How is the Conservancy contributing to Kirtland’s warbler research and conservation?

Dave Ewert: We launched the Kirtland’s Warbler Research and Training Project with the U.S. Forest Service, the Bahamian government and other local partners to train Bahamian biologists to increase conservation capacity in that country and describe the winter habitat requirements of the Kirtland’s warbler and other birds. Since 2002, we’ve banded more than 200 Kirtland’s on Eleuthera and have a better idea of their preferred habitat and food plants. Two of our graduates now work in bird conservation positions in The Bahamas. They help make decisions that conserve Bahamian ecosystems including habitat for Kirtland’s warblers and many other migratory birds that make the Great Lakes region their home each spring and summer.

Nature.org: How can people help the Conservancy protect migratory birds?

Dave Ewert: Financial support from individuals who love birds has been and will continue to be essential to our efforts to protect birds in Wisconsin, the Great Lakes and around the world. Without it, we wouldn’t have been able to educate the students and achieve the success we have in our Kirtland’s warbler training program. We’re seeking support to continue this effort over the next four years, and we invite all bird lovers to join us.

Cate Harrington is a senior conservation writer for The Nature Conservancy.

Photo credits (top to bottom, left to right): Kirtland’s warbler © Janet Clark/TNC; Wildlife biologist Joe Wunderle (seated) and TNC scientist Dave Ewert watch as field assistants survey insects in the leaf litter on Eleuthera Island in the Bahamas © Layne Kennedy