Kirtland’s warblers nearly became extinct in the 1970s. With dangerously dwindling numbers, the U.S. Fish and Wildlife Service created the Kirtland’s Warblers Recovery Team, which continues to work to protect these birds today. In 1987, fewer than 170 singing males had been identified in Michigan. Twenty years later, some 1,800 singing males have been identified.
That’s why Dr. Dave Ewert and Leno Davis’ work matters so deeply. Kirtland’s warblers rely on teams of dedicated conservationists who have not only compiled invaluable data on the tiny songbirds, but have put into action a plan that has exponentially increased the birds’ population.
The small, yellow-bellied birds spend their summers in Michigan and their winters in the Bahamas. You might think that’s not a bad life, but consider this: it takes these one-ounce birds only about two weeks to make that journey, a journey that depends on finding enough food and rest habitat between the Bahamas and northern Michigan.
Most birds—or any other kind of animal—make it difficult to do accurate counts of the entire species, but Kirtland’s warblers are unusually picky in their breeding requirements, which means that the birds counted in a handful of counties in the jack-pine forests of Michigan, Wisconsin and Ontario are likely the only ones in existence.
Jack-pine forests are not typical forests replete with old growth and towering trees. Dry soils and sparse vegetation are hallmarks of jack-pine ecosystems, which depend on fire for their seed combs to open. Kirtland’s warblers will only nest in the jack-pines until the trees reach about 22 feet high; if fire or forest management doesn’t raze trees and revitalize their habitat, the Kirtland’s will abandon the site.
Because fire cannot be used in most of the Kirtland’s preferred breeding habitat, conservationists rely on an intense method of clear-cutting and replanting to mimic fire’s benefits to the jack-pine forests. Success is difficult to define; although populations have rebounded tremendously in the past three decades, they cannot be self-sustaining without fire, forest management, occasional wildfires and management of cowbirds, a nest parasite of the Kirtland’s warbler and many other species.
“It takes a lot of people and a lot of moving parts to keep this bird thriving,” said Dr. Dave Ewert. “But saving a species like the Kirtland’s warbler from extinction is worth it all.”March 02, 2011