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Kirtland's Warbler Increases Range in Wisconsin

Madison - Ten years after Kirtland's Warblers were first documented in Wisconsin, populations of the songbird have increased and their range is expanding through the efforts of state, federal and local partners to increase and manage the endangered bird and its habitat in the state. 

According to the recently released 2017 nesting report released by the U.S. Fish and Wildlife Service, the number of Kirtland's Warblers grew from 11 birds and 3 nests in 2007 to 53 birds and 20 nests in 2017. The population has grown and its range has expanded from Adams County to also include Marinette and Bayfield counties. The birds fledged a minimum of 49 and up to 63 young in 2017. 

“We're very encouraged by results of recent years -- the numbers of birds and nests continues to increase and expand geographically,” said Kim Grveles, a biologist for the Natural Heritage Conservation program of the Department of Natural Resources.

“We look forward to contributing more birds toward the recovery of this species in coming years.” Sarah Warner, wildlife biologist with USFWS, says the progress reflects a decade of conservation work from many enthusiastic and dedicated partners. "We want to thank all of the partners for making this season and the overall effort a success."

Kirtland's is a wood warbler that measures 5.5 inches long, weighs under a half ounce, and migrates from the Great Lakes to the Bahamas for the winter. 

Until 1995, Kirtland's were found almost exclusively in the northern Lower Peninsula of Michigan and were struggling to recover from a steep decline in populations in the 1960s and 1970s due to habitat loss and nest parasitism by Brown-headed Cowbirds.

Davin Lopez, a DNR conservation biologist who co-leads the project with Grveles, says the partners also are working to maintain and expand the mix of 5- to 20-year- old jack pine trees and barrens to provide quality habitat for Kirtland's Warblers and other species.

In addition to DNR and USFWS, partners and collaborators include the University of Wisconsin, Natural Resources Foundation of Wisconsin, USDA Wildlife Services, Sand Valley Restoration Fund LLC, Meteor Timber, the Wisconsin Trapshooting Association, Bayfield, Marinette, Vilas, and Jackson County Forest Departments, and many birders and other private citizens.

The complete Wisconsin Kirtland’s Warbler 2017 Nesting Season Report can be found at

Photo by Joel Trick