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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Endangered Piping Plover and Kirtland’s Warbler See Increases in Population

By Chelsea Richardson

In Michigan there are 12 endangered, nine threatened and one candidate species, as well as two species that have been proposed for listing as endangered.

Piping Plover

Piping Plover. Photo by Rick Baetsen

The term “endangered” means a species is in danger of extinction throughout all or a portion of its range, while the “threatened” designation means a species is likely to become endangered within the foreseeable future.

Endangered species in Michigan include the Michigan monkey-flower,  American burying beetle, Hungerford’s crawling water beetle, karner blue butterfly, Hine’s emerald dragonfly, clubshell, northern riffleshell, rayed bean, snuffbox, Kirtland’s warbler, piping plover, and the Indiana bat.

The State of Michigan has been taking action in helping populations of these endangered species increase. An active recovery program, aided by many volunteers, has helped the piping plover population. The piping plover is a small shorebird that nests on the shores of Lake Michigan and Lake Superior and is listed as an endangered species under the federal Endangered Species Act.  In 2008, there were only 123 piping plovers, 63 breeding pairs. Of those, 53 pairs were found nesting in Michigan while 10 were found in surrounding states. In 2007, the first piping plover nest was discovered in the Great Lakes region of Canada, the first in 30 years. Since then the number of nesting pairs has increased to four. In 2009, a nest was found on the Lake Michigan shoreline in Illinois, also the first to be found in 30 years. Continue reading

ENDANGERED!

At MNA, our Mission is to protect special natural areas and the rare species that live there. The goals of our blog are to cover the latest environmental issues affecting these areas and provide information about the efforts of our volunteers. Our weekly “ENDANGERED!” column serves to inform you about the endangered plant and animal species found in and around these special natural areas, and how you can contribute to conservation efforts before it is too late.

Kirtland’s Warbler
By Brandon Grenier

The Kirtland’s warbler (Dendroica kirtlandii) is in the beginning of a species-recovery success story. Fifteen years ago, it was only known to nest in the northern region of Michigan’s Lower Peninsula. Now, this rare bird is also found in the Upper Peninsula and parts of Canada and Wisconsin. Known to on insects and small fruits, warblers help manage populations of insects such as flies.
Photo by Cindy Mead

Physical Appearance:
The Kirtland’s warbler is approximately six inches in length, and is one of the rarest members of the wood warbler family. It has a bright yellow breast and blue-gray back tail feathers covered in black streaks. The males are songbirds with eyes surrounded by white ringlets. Females are more dull in appearance than their male counterparts, do not sing and do not have ringlet markings. In fall and winter, both sexes have brown plumage, and are much less recognizable.

Preferred Habitat:

This warbler is very particular about where it will nest, nesting only on the ground or in the low hanging branches of jack pine trees. Kirtland’s warblers only nest in trees between the ages of five and twenty; after this the lower branches begin to die and it is no longer suitable. The warbler also requires a large area to sustain populations; each pair typically needs six-to-ten acres for nesting territory. Warblers migrate in the fall to make their voyage to the Bahamas for eight months and return to the Midwest in early May.

Life Cycle:
Once warblers return to Michigan in May, females lay four-to-five eggs, followed by an incubation period of 13-16 days. Both parents help feed the young, which leave the nest within nine days to live on the lowest branches. Parents continue to feed the chicks for five weeks. Most Kirtland’s warblers live for two years.

List Status:
The Kirtland’s warbler is listed as a federal endangered species; however, populations have been improving steadily after a number of programs were enacted to protect its habitat.

Kirtland’s warblers are proof that forest fires are healthy for ecosystems. Jack pine forests were traditionally renewed by forest fires, clearing out old trees and allowing for new growth, and in turn, new nests for warblers. Fires also open the seeds of the pinecones, so when humans prevent natural forest fires to protect their homes and land, the warbler’s habitat is minimized.

The brown-headed cowbird (Molothrus ater) also poses a significant threat to warblers. The cowbird is a nest parasite that lays its eggs in the nests of other birds. The cowbirds’ eggs hatch earlier than other songbirds’, so their young start off stronger and often win fights for food. As the Kirtland’s warbler has no developed defense against this parasitism, cowbirds have ravaged their populations.

Protection Efforts:

The U.S. Fish and Wildlife Service, the USDA Forest Service, the Michigan Department of Natural Resources and the Michigan Audubon Society began working together in 1972 using live traps to catch cowbirds in Kirtland’s warbler breeding areas. Since then, an average of 4,000 cowbirds have been removed per year. The USFWS has also monitored jack pine forests for years, using rotation cuttings, fires and reseeding to maintain breeding areas for warblers. From 167 Kirtland’s warblers in 1974, the number of singing males increased to 1,826 in 2009.

How You Can Help:
You can help ensure the survival of this beautiful bird by:
• Staying out of posted nesting areas
• Camping only in designated campgrounds
• Prohibiting pets from running wild through labeled nesting areas
• Practicing extreme caution with fire
• Tell your friends and family everything you know about this endangered species

MNA volunteers are currently working to protect this and other endangered species, and you can help too. Join our efforts as a volunteer removing invasive plants in the special natural areas where this species lives. Or, become a steward and take responsibility for planning efforts to maintain a specific MNA sanctuary. To find out how to get involved, visit our website.