Michigan Endangered Species: The Kirtland’s Warbler

By Annie Perry, MNA Intern

Swamp Lakes Moose Refuge, one of MNA’s sanctuaries in the Upper Peninsula,. experienced a wildfire in May 2012 that affected 40 acres of the 160-acre sanctuary. The fire caused a reappearance of growth and activity among various species in the sanctuary, including young jack pine stands. This could mean good news for the Kirtland’s warbler, one of Michigan’s endangered species.

Kirtland's warbler

A Kirtland’s warbler.
Photo: Cindy Mead.

Kirtland’s warblers measure about six inches in length. Their backs and wings are bluish-grey with black streaks, and they have yellow breasts and white rings around their eyes. As with many bird species, the females are not as brightly colored as the males.

The Kirtland’s warbler is one of the most geographically restricted mainland birds in the country. They nest on the ground near lower branches and in large stands of young jack pine, which must be 5-20 feet tall and 6-22 years old, according to the U.S. Fish & Wildlife Service. USFWS adds that the age of these trees is crucial to the Kirtland’s warbler’s habitat, though biologists have not yet learned why.

Jack pine stands are historically created and maintained through natural wildfires. After years of suppressing forest fires, scientists realized certain values of fire in forest ecology: for instance, fire helps jack pine cones release all their seeds. Without forest fires, the Kirtland’s warbler was losing its habitat—and, as a result, its population. Jack pine stands are now being managed through timber harvests, burning, seeding, and replanting to ensure the Kirtland’s warbler has its necessary habitat.

The Kirtland’s warbler reached record lows of only 167 singing males in 1974 and 1987. After 1987, however, the population began a dramatic increase. The primary goal of the current Kirtland’s warbler recovery plan was to re-establish a self-sustaining population at a minimum level of 1,000 pairs—a goal which was reached and surpassed in 2001. In 2012, the Kirtland’s warbler reached a record high of 2,090 singing males, up from 1,828 in 2011.

However, the Kirtland’s warbler is not a true self-sustaining population because it continues to persist through intensive management. In order to maintain the Kirtland’s warbler populations, the DNR, the U.S. Forest Service and the U.S. Fish and Wildlife Service continue to manage the jack pine stands. They also control the cowbird population, a bird which acts as a parasite of Kirtland’s warblers’ nests. According to a five-year review published in August 2012 by the U.S. Fish and Wildlife Service, a true self-sustaining population—one that is free from intensive management—is currently impossible.

The Department of Natural Resources has tips for helping sustain Kirtland’s warbler populations, including staying out of posted nesting areas, camping only in designated campgrounds, staying with tour guides and leaving pets in a safe area. For more information on the Kirtland’s warbler, check out its webpage through the U.S. Fish & Wildlife Service.

If you’re interested in seeing the recovery of MNA’s Swamp Lakes Moose Refuge nearly a year after the wildfire, MNA will host a fire ecology tour at the sanctuary on May 18. See the Calendar of Events or email Adrienne Bozic at abozic@michigannature.org for details. RSVPs are required.

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MNA’s Swamp Lakes Moose Refuge Impacted by Duck Lake Fire

By Adrienne Bozic and Chelsea Richardson

Swamp Lakes Moose Refuge Fire Damage

Some of the fire damage at Swamp Lakes Moose Refuge. Photo by Adrienne Bozic

On May 23, a lightning strike sparked a wildfire that burned more than 21,000 acres in the eastern Upper Peninsula, the third largest Michigan wildfire in modern history. This fire burned for 20 days before it was considered 100 percent contained.

The toll on local homeowners was devastating; the fire destroyed 136 structures, including 47 homes, a store, and the famous Rainbow Lodge at the mouth of the Two Hearted River. The fire stretched all the way to Lake Superior, almost thirteen miles north of its southern extent. At final tally, the fire burned 21,069 acres, making it the third-largest wildfire in modern Michigan history after the 25,000-acre Mack Lake Fire (1980) and the 72,000-acre Seney Fire (1976).

A total of 300 personnel assisted with the Duck Lake Fire, building 42.6 miles of fire line, almost half of them dug by hand. Cooperating agencies included the Michigan State Police, Luce County Sheriff’s Department, Luce County Emergency Management, Wisconsin DNR, American Red Cross and Salvation Army. Many news reports noted that Luce County and Newberry residents would line the streets in the evening as fire personnel drove home for the night, cheering loudly and holding signs thanking them for their hard work.

Bracken Fern Sprouting

Some signs of life at the sanctuary as bracken fern sprouts from the soil. Photo by Adrienne Bozic

Many natural areas in Luce County were affected by the fire, which can have potentially positive ecological responses in fire-adapted ecosystems such as those found in the Duck Lake fire area. Many ecosystems throughout Michigan are fire-dependent and require periodic fire to maintain their specific ecology and function. According to the DNR website, prescribed fire is also used to maintain habitats such as prairies. Many endangered species depend on warm season grasses and prairie remnants for their survival. Fire is also used to maintain large openings and oak savannahs. Savannahs are open, park-like areas with scattered trees. These areas need periodic fires to keep brush and trees from turning them into a forest.

A portion of MNA’s Swamp Lakes Moose Refuge was burned in the Duck Lake fire. On June 26, MNA’s Upper Peninsula Regional Stewardship Organizer Adrienne Bozic visited the sanctuary to survey the fire damage. Approximately 40 acres of the 160-acre sanctuary were affected, mainly along the southern tier of the property. The fire exhibited interesting behavior south of Pike Lake, possibly due to varying forest types present which have differing levels of combustibility and burn at different rates. For example, in Swamp Lakes, the fire abruptly stopped at areas dominated by broad-leaved hardwoods such as maple, which presumably formed a fire break of less-flammable material. Continue reading