The Kirtland’s Warbler 2010 Population Study

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Male Kirtland's Warbler

Press release: The Michigan Department of Natural Resources and Environment released their annual survey information indicating the state’s population of the endangered Kirtland’s warbler remains steady.

Biologists, researchers and volunteers in Michigan observed 1,733 singing males during the official 2010 survey period. The lowest numbers were recorded in 1974 and 1987, when only 167 singing males were found.

Warblers are detected by listening for their songs which 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 2010 survey was a joint effort by the DNRE, 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 (178), Clare (99), Crawford (288), Iosco (167), Kalkaska (60), Montmorency (28), Ogemaw (552), Oscoda (256), Otsego (24), Presque Isle (6), and Roscommon (41). Surveyors identified 29 singing males in five Upper Peninsula counties: Baraga (3), Chippewa (15), Delta (7), Marquette (5), and Schoolcraft (4). Twenty-six additional singing males were observed outside Michigan: 23 in Wisconsin and three in Ontario.

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Female Kirtland's Warbler

As the amount of habitat has stabilized, the population of warblers has stabilized in 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.

To mimic the effects of wildfire and ensure the future Kirtland’s warblers, the DNRE and its partners manage the forests through a combination of clear-cutting, burning, seeding, and replanting that promotes habitat for many species, including deer, snowshoe hare, other warbler species, and rare plants, in addition to Kirtland’s warblers.

Kirtland's Warblers breed in upper and lower Michigan and winter throughout the Bahama Islands.

For more information on the Kirtland’s warbler, contact the DNRE Wildlife Division, Natural Heritage Program, Box 30444, Lansing, MI 48909, or visit the DNRE website: www.michigan.gov/dnre or the U.S. Fish and Wildlife Service’s Kirtland's Warbler Fact Sheet.