October 22, 2018|By Katie Valentine
 Fifty years ago, the Kirtland’s Warbler was on the brink. Its North American habitat had shrunk dramatically, and that loss, combined with pressure from brown-headed cowbirds, had caused its numbers to drop to just 330 individuals—the species’ lowest recorded population in history. Due to these threats, the Kirtland’s Warbler was listed as endangered under the Endangered Species Preservation Act on March 11, 1967. 

10 22 Male Kirtlands warbler Joel TrickUSFWSMale Kirtland's Warblers’ summer plumage is composed of a distinctive bright yellow colored breast streaked in black and bluish gray back feathers, a dark mask over its face with white eye rings, and bobbing tail. Photo by Joel Trick/USFWS.

The warbler’s situation looked dire, but thanks to intensive conservation efforts, the species is poised to make a big comeback. The bird has bounced back heartily from its previously low numbers: right now, scientists estimate that the Kirtland’s Warbler’s population totals over 2,000 pairs. This positive trend prompted the U.S. Fish and Wildlife Service (USFWS) to announce in April its proposal to delist the Kirtland’s Warbler from the federal Endangered Species List, where it’s been listed as endangered for over 50 years. This is good news, as delisting a species means that conservation efforts have worked to increase its numbers. The agency is now reviewing the comments it received during its 90-day comment period on the delisting proposal, and once it finishes, will make a final decision on whether to delist the bird.



“The reason a species like this comes off the Endangered Species List is that its habitat has been secured and being allowed to expand.” says Tom Duffus, Vice President and Northeast Representative for The Conservation Fund. “This is a story of: If you build it, they will come.”

Habitat is, in fact, particularly important to the Kirtland’s Warbler. The bird, which has long been known to have a limited range, is very picky about where it builds its nests: it chooses only young jack pine trees, ideally of a certain height (5 to 16 feet tall) and spacing. Typically, these types of forests grow up after wildfires, so as the Upper Midwest has become more developed and forest fires have become scarcer, the birds’ numbers have dropped. 

10 22 Warbler 3 Joel TrickUSFWSThe Kirtland's Warbler is a small (<6”) songbird that nests in young jack pine stands in northern Michigan, Wisconsin, and Ontario. This species has one of the most geographically restricted breeding distributions of any mainland bird in the continental United States. They migrate from their nesting grounds to the southeastern coast of the United States on their way to wintering grounds in the Bahamas. Photo by Joel Trick/USFWS.

As the birds’ numbers rebound, however, they’ll need more of this habitat. That’s where The Conservation Fund comes in. In 2015, we secured funding from the U.S. Forest Service’s Forest Legacy Program to establish a working forest conservation easement on 65,807 acres in Wisconsin’s Brule-St. Croix Legacy Forest. This endeavor stands as the largest land conservation effort in the state’s history. The forest contains young jack pine habitat that’s ideal for warblers and is adjacent to land where Kirtland’s Warblers have been confirmed. So, as the bird’s population grows, the Brule-St. Croix Legacy Forest “should be great for Kirtland’s,” according to Bob Hanson of the Wisconsin DNR. 

“This area is coming back very well to jack pine barrens and the plan is to let it continue to come back naturally,” Hanson said, adding that he thinks the birds will find the area “in a few more years.” 

10 22 StCroixBrule Wisconsin ColdsnapPhotography 008Brule-St. Croix Legacy Forest in Wisconsin. Photo by Coldsnap Photography.

The Wisconsin DNR has been playing recordings of Kirtland’s Warblers in order to attract them to nearby forests, an effort that a recent study found has been working. On top of that, they’ve been tackling the issue of brown-headed cowbirds head-on. Brown-headed cowbirds are a parasitic bird that lays its eggs in other birds’ nests, a behavior that’s contributed to the Kirtland’s Warbler’s decline. Once the cowbird eggs hatch, the Kirtland’s Warbler raises the cowbirds as its own – often to the detriment (or demise) of its own chicks. The Wisconsin Department of Natural Resources has been trapping cowbirds in areas near Kirtland’s Warbler habitat, a practice that’s legal in the state under the Migratory Bird Treaty Act. 

The Brule-St. Croix forest is a working forest, meaning it’s used for timber management. Forests that are part of The Conservation Fund’s Working Forest Fund receive expert management. In the case of Brule-St. Croix, and in the absence of any practical use of prescribed fire, that management involves a conservation easement that requires habitat maintenance for Kirtland’s Warblers and other birds, including the Golden-winged Warbler and Sharp-tailed Grouse. There are consistently young, middle, and older trees across the forest, making it perfect for the Kirtland’s Warbler.

“The Brule St.-Croix Legacy Forest is very much intended to secure habitat of the Kirtland’s Warbler and other birds, so that those birds would expand into the area,” Duffus said. “Once you have conserved this habitat and put it under a habitat regime as we’ve done it provides a hope for the species.”

10 22 StCroixBrule Wisconsin ColdsnapPhotography 009Brule-St. Croix Legacy Forest in Wisconsin. Photo by Coldsnap Photography.

This forest isn’t The Conservation Fund's only project that is helping the warbler succeed. We conserved 150 acres in the Huron-Manistee National Forest in Michigan, an area that’s been classified as essential nesting habitat for Kirtland’s Warblers. In addition, The Conservation Fund played a pivotal role in setting up a $1 million fund devoted to the protection of Kirtland’s Warblers as part of the Enbridge 6B Mitigation Program. In September, we transferred $100,000 to the Michigan Department of Natural Resources for Kirtland’s Warbler conservation efforts, funding that came through our mitigation partnership with Enbridge’s proposed NEXUS gas transmission system. 

If the Kirtland’s Warbler is delisted, the USFWS’s job won’t be over: the agency, along with some state agencies, will continue to monitor the species for at least five years to make sure its numbers don’t plummet. The USFWS, for its part, credits a range of stakeholders for the bird’s upswing in numbers.

“Without a doubt, this bird’s recovery is the result of cooperation among states, local residents, federal agencies and conservation groups,” said Tom Melius, USFWS Midwest Regional Director in a press release. “This dedicated conservation community is committed to addressing the needs of the Kirtland’s Warbler into the future.”


10 22 Working Forest Fund

To learn more about The Conservation Fund’s Working Forest Fund—and the wildlife, ecosystems and job opportunities it protects—click here.