Kirtland’s Warbler Continues to Exceed Recovery Goal According to a press release from the Michigan DNR, biologists, researchers and volunteers in Michigan observed 1,805 singing male Kirtland's Warbler 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.