The Michigan Department of Natural Resources today released annual survey information indicating the state’s population of the endangered Kirtland’s warbler remains steady.
Biologists, researchers and volunteers in Michigan observed 1,805 singing males during the official 2011 survey period — 1,747 males were observed in 2010. The population has not increased or decreased by more than 5 percent since 2007. The lowest numbers were recorded in 1974 and 1987, when only 167 singing males were found.
The Kirtland’s warbler survey is conducted each year during the second and third weeks of June when the birds are defending their nesting territories. Warblers are detected by listening for their songs. The songs can be heard at distances up to one-quarter mile, providing an excellent way to detect the birds with minimum disturbance. Only the males sing, so estimates of breeding population size are obtained by doubling the number of singing males recorded, based on the assumption that each male has a mate in its territory.
The 2011 survey was a joint effort by the DNR, U.S. Forest Service, U.S. Fish and Wildlife Service, Michigan Department of Veterans and Military Affairs, Michigan Audubon Society, and citizen volunteers.
This year, singing males (numbers in parentheses) were found in 11 Northern Lower Peninsula counties: Alcona (221), Clare (84), Crawford (315), Iosco (134), Kalkaska (53), Montmorency (32), Ogemaw (569), Oscoda (261), Otsego (31), Presque Isle (5), and Roscommon (65). Surveyors identified 35 singing males in seven Upper Peninsula counties: Alger (1), Baraga (2), Chippewa (14), Delta (11), Luce (3), Marquette (2), and Schoolcraft (2). Twenty-three additional singing males were observed outside Michigan in Wisconsin (21) and Ontario (2).
As the amount of nesting habitat has stabilized, the population of warblers has also stabilized in the core of the range: northern Michigan’s jack pine barrens ecosystem. The warblers nest on the ground and typically select nesting sites in stands of jack pine between four and 20 years old. Historically, these stands of young jack pine were created by natural wildfires that frequently swept through northern Michigan. Modern fire suppression programs altered this natural process, reducing Kirtland’s warbler habitat. The result was that the population of Kirtland’s warblers declined to the point that they were listed as endangered.
To mimic the effects of wildfire and ensure the future of this species, the DNR, U.S. Forest Service, and U.S. Fish and Wildlife Service manage the forests through a combination of clearcutting, burning, seeding and replanting to promote habitat for many species, including snowshoe hare, other warbler species, and rare plants. Because large prescribed fires are neither safe nor economical in northern Michigan, approximately 3,000 acres of jack pine trees are harvested and replanted annually on state and federal lands. This use of public lands creates jobs, provides habitat for Kirtland’s warblers and other species, and brings to northern Michigan birders and hunters from across the state and around the world.
“Warblers create jobs,” said DNR Endangered Species Coordinator Chris Hoving. “From tourism to festivals to forest products, this endangered species directly or indirectly contributes to the economic activity of rural northern Michigan.”
“The Kirtland’s warbler habitat program is successful because there are many benefits,” said Keith Kintigh, DNR wildlife ecologist. “Not only are we providing habitat for an endangered species, we are also providing wood products and great hunting opportunities for snowshoe hare, deer and turkey, to name a few.”
For more information on the Kirtland’s warbler, visit the DNR website: www.michigan.gov/dnr (click on wildlife and habitat, then wildlife species and then birds).
The Michigan Department of Natural Resources is committed to the conservation, protection, management, use and enjoyment of the state’s natural and cultural resources for current and future generations. For more information, go to www.michigan.gov/dnr.