A team of conservation experts is conducting a long-term plan to stabilize the population of Kirtland’s warbler.
According to the 2025 census, there has been a decline in the population of the once-endangered songbird. The survey indicated that there were 1,477 breeding pairs of the Kirtland’s warblers in Michigan, which is home to 98% of the population.
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Another 12 pairs were counted in Wisconsin, with Ontario’s numbers yet to be reported.
According to the Michigan Department of Natural Resources (DNR), the songbird’s population decline is projected to continue over the next few years before the Kirtland’s Warbler Conservation Team’s efforts can stabilize the population.
The Kirtland’s Warbler Conservation Team consists of partner organizations, including the Michigan DNR, U.S. Fish and Wildlife Service, U.S. Forest Service, Wisconsin DNR, American Bird Conservancy, Huron Pines and others.
“This is a situation we’ve been monitoring and addressing for several years now,” said Erin Victory, a wildlife biologist and Kirtland’s warbler management coordinator for the Michigan DNR. “From a habitat management perspective, we anticipated a decline in the population and have been taking action to address it. We are confident we have enough tools and resources available to us, collectively within the conservation team, to reverse the decline and stabilize the population.”
A survey was conducted in Michigan from June 6 to June 26 in the northern Lower Peninsula and Upper Peninsula. Here’s what officials found:
- 814 pairs of Kirtland’s warblers on DNR-managed land in the northern Lower Peninsula.
- 597 pairs on Forest Service land in the northern Lower Peninsula.
- 49 pairs on DNR-managed land in the Upper Peninsula.
- 17 pairs on Forest Service land in the Upper Peninsula.
The Michigan DNR stated that small numbers of the songbird are also found in Wisconsin and Ontario.
Why Kirtland’s warbler’s population is declining
According to the Michigan DNR, a reduced acreage of suitable breeding habitat is one of the reasons for the population decline.
The ground-nesting Kirtland’s warbler relies only on young jack pine forests to breed, with the majority of the birds living in northern Lower Michigan.
The DNR said there are not enough young jack pine stands available to maintain a stable population of the songbirds.
Brown-headed cowbird nest parasitism is another factor in the population decline. This is when cowbirds lay eggs in Kirtland’s warblers’ nests, as well as those of other bird species. The larger cowbird chicks then out-compete warbler chicks for food, causing the songbirds to die while the warbler parents unknowingly raise the cowbird chicks.
Unforeseen factors affect the Kirtland warbler’s population as well. According to the DNR, a 2023 hailstorm wiped out half of the jack pine seedlings at a DNR-contracted nursery. Hurricanes during migration and dry winters can stress or kill birds, with fewer birds returning to Michigan.
Conservation team’s plan
The conservation team is developing a 10-year Breeding Rand Conservation Plan to manage the habitat, primarily, using novel approaches to cut jack pine stands in the surplus 20 and 30-year age classes, along with 60-year-old stands, to ensure the annual habitat goals are met.
The DNR said previous management practices on handling jack pine stands need to be updated. The stands are not commercials marketable for clearcutting until they are at least 60 years old because they were intentionally planted at higher densities for better habitat. This led to land managers having less opportunity to create young habitat over the last decade.
The DNR said to the extent possible, the younger timber will be sold as mulch or as a renewable energy resource on the biomass market. Land managers are also evaluating the feasibility and safety of increasing prescribed fire use.
“This strategy continues to create habitat and also allows the 40-year age class to continue growing and become merchantable. If we kept trying to harvest from the 40-year age class, we would be perpetuating the problem,” said Jason Hartman, silvicultural specialist for the Michigan DNR. This strategy will benefit local economies, Kirtland’s warblers and other species associated with the jack pine ecosystem.
Other strategies include transitions away from jack pine plantations where possible in favor of lower-cost natural regeneration and partnering with university researchers to evaluate new habitat management techniques.
The team will also monitor brown-headed cowbird nest parasitism.
Once endangered species
The Kirtland’s warbler was federally endangered for nearly 50 years.
According to the DNR, the population dropped to fewer than 200 pairs in the 1970s and again in the 1980s when the population was restricted to only 14 townships in six counties in northern Lower Michigan.
Thanks to a decades-long, collaborative effort to recover the species by federal, state and private partners, the bird was removed from the federal endangered species list in 2019.
However, the songbird remains a state-threatened species in Michigan because it will not persist without intensive management.