NORTHERN MICHIGAN – A team of conservation experts from state and federal agencies and nonprofits is launching a long-term plan to stabilize the once-endangered Kirtland’s warbler population.
The 2025 census shows a decline, with 1,477 breeding pairs in Michigan—home to 98% of the global total—and 12 in Wisconsin. Ontario’s numbers are pending, for a preliminary total of 1,489 pairs, down from 2,245 in 2021.
The Kirtland’s Warbler Conservation Team—a coalition including the Michigan DNR, U.S. Fish and Wildlife Service, U.S. Forest Service, Wisconsin DNR, American Bird Conservancy, Huron Pines, and others—is responding with updated habitat strategies.
“This is a situation we’ve been monitoring and addressing for several years now,” said Erin Victory, wildlife biologist and Kirtland’s warbler coordinator for the Michigan DNR. “We are confident we have enough tools and resources… to reverse the decline and stabilize the population.”
Surveys conducted in June across Michigan found:
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814 pairs on DNR-managed land (northern Lower Peninsula)
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597 pairs on Forest Service land (northern Lower Peninsula)
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49 pairs on DNR land and 17 on Forest Service land (Upper Peninsula)
The warbler nests exclusively in young jack pine forests. A shortage of suitable habitat—particularly stands 6–20 years old—is a primary cause of the decline. Most remaining trees are 30–40 years old and won’t be commercially viable for harvesting until about 60, making it difficult to create new habitat.
“While a population decline is not what we wanted… it is encouraging that we already understand the principal cause,” said Steve Roels, conservation team coordinator.
The team is finalizing a 10-year Breeding Range Conservation Plan. Key strategies include harvesting younger jack pine (20–30 years old), selling it for mulch or biomass fuel, and using more prescribed burns.
“This strategy continues to create habitat and also allows the 40-year age class to continue growing,” said Jason Hartman, DNR silvicultural specialist. “If we kept trying to harvest from the 40-year age class we would be perpetuating the problem.”
Other tactics include shifting to natural regeneration where possible, partnering with researchers on habitat innovations, and monitoring brown-headed cowbird nest parasitism, which threatens warbler chicks.
Unpredictable events have also impacted the bird’s numbers. A 2023 hailstorm destroyed half of the DNR’s jack pine seedlings. Wildfires, hurricanes during migration, and drought in the Bahamas (the bird’s wintering grounds) can further reduce survival rates.
“The decline… is likely due to a decline in available breeding habitat, but there are other factors that we can’t control,” Victory said.
Once down to fewer than 200 pairs in the 1970s and 1980s, the Kirtland’s warbler rebounded through decades of coordinated conservation. It was delisted federally in 2019 but remains state-threatened and dependent on active management.
“The Kirtland’s Warbler Conservation Team is a highly collaborative group… I am confident that this group will continue to do what is necessary,” said Phil Huber, team chair.
Surveys have been conducted since 1951. Full censuses occur every 2–4 years. Singing males—each assumed to have a mate—are counted to estimate breeding pairs.
Victory said future surveys may show a continued dip below the 1,000-pair threshold but remains hopeful.
“The real strength of the management… lies in the collective efforts of the conservation team,” she said. “These collaborations will continue to be a driving force.”
