Kirtlands Warbler

Interesting Fact: The Kirtland's warbler was one of the first species to be listed as endangered after the Endangered Species Act of 1973 was passed by Congress.

Kirtlands Warbler

Story of a Rare Bird: The Kirtland's warbler, a ground nesting, persistent singer was first discovered in 1851 on the farm of Dr. Jared Kirtland near Cleveland, Ohio. The Kirtland’s warbler is a small, blue-gray bird with a lemon-yellow breast, which constantly twitches its tail feathers while perching. The Kirtland’s warblers’ rareness kept its nesting habitat from being discovered until 1903 when two men fishing on the Au Sable River found one of the birds. The discovery of the bird prompted a search of the area to find more of the species. After months of searching, an avid ornithologist found a pair of the birds nesting on the ground in a large tract of young jack pine.

 

Brown-headed Cowbird Threats

Today, the Kirtland's warbler faces two significant threats: lack of crucial young jack pine forest habitat and the parasitic cowbird.

Each Kirtland warbler weighs less than an ounce, no more than the weight of six Hershey kisses. A young jack pine forest needs to be at least 80 acres to attract breeding Kirtland’s warblers, although each pair needs about 15 acres to raise a nest of young. In the 1950’s, “Project Pop-Cone” began, which was a series of prescribed burns that mimic natural fire conditions are used to create new nesting habitat for the Kirtland’s warbler. Intense heat is needed for the cone on the jack pine to pop and scatter the seeds needed for natural regeneration. Wildfires are the natural method of releasing the seeds, or were before fire suppression practices began. Human efficiency at suppressing wildfires, while good for homes and towns, threaten the birds’ ability to produce young.

Its exacting nesting habitat requirements and a second problem, the cowbird, caused a drastic decline in the Kirtland's warbler's numbers. The cowbird is a parasitic bird that lays its eggs in warbler nests. Their larger, more aggressive off-spring takes most of the food provided by adult warblers, leaving the warbler hatchlings to starve. The combination of these two problems led the U.S. Fish and Wildlife Service to list the Kirtland's warbler as an endangered species in 1973.

 

Management

Today, Kirtland's warblers are found in only ten counties on Michigan's northern Lower Peninsula and four counties in the Upper Peninsula. Until 1995 they had never been known to nest on the Upper Peninsula. Kirtland's warblers migrate from Michigan to the southeastern coast of the United States on their way to wintering grounds in the Bahamas.

Efforts in Michigan have caused a rise in Kirtland’s warbler populations. In 1958, three separate tracts on state forest land in three counties that totaled 11 square miles were reserved as management areas for the warbler. A few years later, 4,010 acres of the Huron National Forest were also dedicated to the warbler. Today, over 190,00 acres of public land are managed to meet the needs of the Kirtland's warbler and the wide variety of species associated with the jack pine ecosystem. Public entry into occupied areas from May 1 through August 15 is by permit only, to minimize disturbance and provide protection to the bird during the nesting season.

 

Census

The Huron-Manistee National Forest, U.S. Fish and Wildlife Service, and Michigan Department of Resources monitor the population by conducting an annual census of Kirtland's warblers. In 2008 a record 1,792 singing males were counted. The population has been increasing since the 1990's, after reach an alltime low of 167 singing males during the 1987 census.

 

Bahamas

Most habitat conservation efforts focus on habitat in the boundaries of the United States. Each year millions of dollars are spent on maintaining old and creating new habitat for threatened and endangered bird species. This work has been successful for many species and prompted recoveries of species populations. But there are birds that don’t live in just the United States. Some choose to winter where the weather is warm and sunny. The endangered Kirtland’s warbler is such a bird. As a result of the Kirtland's warbler spending winters in the Bahama's, a partnership between the Bahamas National Trust (link) and U.S. Forest Service has developed.

In 1997 and 1998 Phil Huber from the Huron Manistee National Forests’ Mio Ranger District went to the Bahamas to search for the Kirtland’s warbler and begin establishing contacts to study the Kirtland’s warbler’s winter habitat. Since that time, members of the research team have worked on project research, fieldwork, and training interns to find and observe the warbler.





https://www.fs.usda.gov/detail/hmnf/learning/?cid=STELPRDB5143174