Minnesota warbler candiate for 'endangered'

The Golden-winged Warbler, with an estimated 40 percent of its world population breeding in Minnesota, might warrant federal protection as a threatened or endangered species. The U.S. Fish and Wildlife Service made that announcement Thursday. The announcement follows an initial review of a petition seeking to protect the Golden-winged Warbler under the Endangered Species Act.

Golden-winged Warblers use deciduous woodlands, usually in dry uplands or areas of thick undergrowth in swampy areas, according to the USFWS. The birds are found in early successional vegetation such as old fields, power line corridors, stream borders, alder and coniferous (spruce/tamarack) bogs.

In Minnesota, they nest in the northeastern third of the state, essentially northeast of a line from Hinckley to Thief River Falls.

Golden-Winged Warbler populations have been declining because of poor reproductive success, the USFWS said. This is in part due to brown-headed Cowbird parasitism, high rates of nest predation, and hybridization and competition associated with Blue-winged Warblers.

Loss of early-successional habitat to forest maturation, human development, and wetland loss also may be contributing factors to declining populations. Availability of the warbler's preferred habitat has declined because of forest maturation in general, reduced timber harvest, and effective wildfire prevention. (Wildfire stimulates the new growth which the warblers use.)

Thls photo of a Golden-winged Warbler was taken in Burnett County in northwestern Wisconsin last spring.