Kirtland's Warbler (Dendroica kirtlandii)

Kirtland's WarblerKirtland's Warbler distribution map


Population Information

Monitoring by WDNR and US F&WS personnel in jack pine forests in Wisconsin has turned up singing males in a few counties in northern and west-central Wisconsin. No confirmed breeding has been documented in Wisconsin. Breeding evidence has recently been confirmed in the Upper Peninsula of Michigan.

Life History Breeding

Habitat Selection

Most nesting Kirtland’s Warblers in Michigan choose extensive jack pine forests, usually in patches greater than 200 ha (500 acres) in area, and most often in tracts much larger in area. Jack pines in areas favored by this species are from 1.5 to 2 meters (5.0-6.5 feet) tall, when these birds first begin to use an area. These locations continue to be used until the trees reach a height of approximately 5 meters (16 feet). This species nests on the ground, concealing the nest among grasses, often at the base of pines. Nearby vegetation may include grasses, sedges, cherry, blueberry, and ferns. Needles from nearby pines along with oak leaves are mixed with these understory plants (Mayfield 1992).

Though there are as yet no confirmed breeding records for WI, singing summer males have been recorded in Douglas, Jackson, Marinette, Vilas, and Washburn counties. Beginning with the year 1978, a concerted effort was made by WDNR personnel and others to find evidence of breeding. Only singing males had been located through the late 1980s, and no females (Robbins 1991). Work for the Wisconsin Breeding Bird Atlas in the 1990s recorded birds in Vilas and Marinette counties (see atlas map above). Jim Baughman (pers. comm.) reported a singing male on the Vilas County Forest during the spring of 2003.

Habitat Availability

Areas of jack pines suitable for Kirtland’s Warbler exist in several WI locations, as the presence of occasional singing males proves. Potential areas for Kirtland’s Warbler in Wisconsin include Jackson County (Black River State Forest), pine barrens in the Chequamegon National Forest in Bayfield County (Swengel 2000), portions of the Nicolet National Forest in Eastern Oconto County, the Marinette County Forest in western Marinette County, the Vilas County Forest, and on the Northern Highland State Forest in portions of Oneida and Vilas Counties. Unfortunately jack pine acreage statewide has been steadily decreasing (WIDNR 2002)

Population Concerns

The Kirtland’s Warbler is one of the rarest of North American birds. Recent reproductive success in Michigan, aided by efficient cowbird control and habitat management specifically directed at maintaining numbers of this species seem to be helping as populations of this species remain relatively stable. Dangers including breeding habitat loss and degradation due to a reduction in fires and forestry practices, potential loss of critical wintering habitat, a diminished but continuing threat of cowbird parasitism, physical dangers to migrants en route (extreme weather events, tower kills, etc.) continue to exist and will likely not be completely eliminated (Mayfield 1992). If additional small breeding populations can be located in WI, northern Michigan, Ontario, or Quebec, their very small numbers probably could not augment the overall population to any great extent, but it is impossible to assess this without further monitoring. Wintering habitat has thus far been stable, but since it occupies such a limited area, protection of the scrub vegetation used by this species should be a priority (Mayfield 1992).

Recommended Management

Large block jack pine habitat should be maintained at different successional stages and managed on a rotational basis. Public lands, most likely in Federal, state or county ownership, may provide the best opportunities to provide the frequent use of fire and intensive management efforts needed to provide habitat for this species. Maintaining areas of young jack pine through harvest, planting and fire along with the trapping of cowbirds, have been the primary methods for managing the Kirtland’s warbler populations in Michigan. Cowbird control (trapping) has caused parasitism to decline to only 3%. Increases in Kirtland’s warbler populations have only occurred following a major fire, but habitat management undoubtedly has played an important role.

Research Needs

Since the presence of this species in Wisconsin has until now been limited to a few singing males, continued monitoring for additional birds and possible breeding evidence is a priority. Research should focus on why this species is found in only an extremely small part of the range of jack pine. In the MI jack pine forests, the soil type is Grayling sand, a very fast-draining soil. Since this species nests on the ground, this soil protects nests after heavy rains, when nests might be flooded if located on another slower-draining soil. Other habitat features may be equally important, but not yet known. Since the species’ range during the Pleistocene was undoubtedly on other soil types, this aspect of its nesting ecology merits additional work (Askins 2000).

Information Sources


Contact Info

Kreitinger, K., Y. Steele and A. Paulios, editors. 2013.
The Wisconsin All-bird Conservation Plan, Version 2.0. Wisconsin Bird Conservation Initiative.
Wisconsin Department of Natural Resources. Madison, WI.

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