By Peter Dieser
Since 1938, Tamarac National Wildlife Refuge has been an important breeding ground and sanctuary for migratory birds. Since 1987, the northwest Minnesota refuge has been vital to the reintroduction of trumpeter swans to the state. Today, Tamarac Refuge is leading the recovery of another avian species of concern, the golden-winged warbler.
The golden-winged warbler has suffered one of the steepest population declines of any North American songbird. In recent decades, about 60 percent of the bird’s historical population has disappeared across its migratory range from the north-central/northeastern United States (summer) to Central and South America (winter).
Minnesota is a key state for the bird’s conservation because up to half of the remaining population breeds there each summer. Tamarac Refuge has one of the highest densities of nesting pairs in the world.
“Due to ideal habitat conditions associated with a diverse and healthy forest, Tamarac Refuge has an abundant population of golden-winged warblers and a stewardship responsibility to lead the way in the golden-winged warbler conservation initiative by maintaining our resident population,” says refuge senior wildlife biologist Wayne Brininger.
The male is a breathtaking songbird, with yellow wing bars, a striking black throat patch and mask and a golden crown. The females are similar, though their yellow wing bars and crown are more muted and their mask and throat patch are gray. Only five inches long, this songbird requires diverse habitat to breed and forage.
The golden-winged warbler is often called a young forest specialist because it nests on the ground in deciduous forest openings, but it requires an even more diverse mix of young and mature habitat.
To nest, breed and rear young, the bird requires a mix of woody shrubs, singly spaced or clumped mature trees and open ground containing forb species, such as goldenrod, aster and milkweed. Nesting habitat must also be adjacent to mature deciduous forest, where the bird forages once chicks have fledged and nests are abandoned.
The forest openings are ephemeral (short-lived) habitat created through natural disturbances such as low-to-moderate fire and tree blowdowns or mechanical maintenance such as timber harvest and brush clearing. Because the golden-winged warbler requires a dynamic mix of forest types, its habitat serves other wildlife, too.
“Maintaining golden-winged warbler habitat also directly benefits numerous game and nongame species, including pollinators, small and medium mammals, songbirds and other species of concern in Minnesota, such as the American woodcock,” says refuge manager Neil Powers.
Since 2013, the American Bird Conservancy (ABC) and Tamarac Refuge have partnered to help restore and maintain golden-winged warbler habitat throughout northern Minnesota.
The partnership has restored 729 acres of high-quality nesting habitat on the refuge, and more is planned. With a grant from the Minnesota Outdoor Heritage Fund, ABC has restored an additional 1,053 acres of nesting habitat in the state. Up to 1,000 more acres per year on public lands in Minnesota are planned over the next decade.
In 2015, the U.S. Fish and Wildlife Service and the Red Lake Band of Chippewa signed a memorandum of understanding (MOU) to restore up to 1,000 acres per year of golden-winged warbler habitat on tribal lands. The MOU is effective for the next 12 years; the work will be done with assistance from ABC. This effort is a tremendous opportunity to continue to raise public awareness and improve golden-winged warbler habitat across northern Minnesota.
“We are proud of what we have accomplished here on the refuge,” says Powers, “but we are equally proud to be a part of a conservation community that continues to work together to maintain a healthy and diverse natural landscape throughout the state.”
Peter Dieser is a Minnesota-based public lands coordinator for the American Bird Conservancy.