Kirtland's Warbler: could this rare bird be nesting here?

Is it possible that America's rarest warbler could be nesting in Minnesota? Birders will begin searching this spring, starting in Pine County. Volunteers are wanted.

The bird is Kirtland's Warbler, until 10 years ago found exclusively in areas of jack pine in Michigan's the upper and lower peninsulas. Since then, the species has expanded in small numbers to Wisconsin and Ontario.

The birds have had success in Wisconsin. The first nesting was found in Adams County, 200 miles east of Minneapolis.

The Minnesota search project will be discussed April 9 from 7 to 8:45 p.m. at the Southdale library, 700l York Ave. S. The meeting room is on the second floor.

The bird's necessary jack-pine habitat is found in abundance in north-central and northeastern Minnesota. The tree likes poor, sandy soil. Pine County is considered a good place to start.

Kirtland's is a very particular specialist. It nests on the ground in grass under the lowest branches of jack pines less than 20 years old, preferring trees 16-20 feet high.

Wild fire once created nesting opportunities by burning pine stands that would regrow to appropriate size.

Today, with fire a danger to humans and structures, the bird depends on humans to create and manage its habitat. The Wisconsin Department of Natural Resources has been active in this these efforts, as have volunteer organizations.

Another problem for the bird is usurpation of its nests by cowbirds. The latter lay eggs for the warbler to incubate, reducing the likelihood of warbler chicks hatching or maturing. Warbler eggs sometimes are removed from the nest by the cowbirds.

Cowbirds are trapped and removed at the Kirtland's site in central Michigan.

The bird was listed as an endangered species in 1967. Population of the warbler, yellow and gray with black markings, fell to as few as 167 males in 1987.

In 2015 teams of counters found 2,355 singing males in all locations where the birds have been found. There are more today. It would be very exciting if Minnesota could become part of this successful expansion effort.

The bird presently is listed as accidental by the Minnesota Ornithologists' Union, the state bird club. Accidental species are those least likely to be seen here.