Three nests of the rare Kirtland’s warbler have been discovered in the state, which wildlife authorities say shows recovery efforts for the endangered species are working.

“It’s a historic moment not only for the conservation of species,” said Sumner Matteson, an avian ecologist at the Wisconsin Department of Natural Resources, “but a historic moment in the history of ornithology.”

About two weeks ago, a bird watcher in central Wisconsin reported seeing a nest, indicating that a breeding pair now calls the state home.

Since then, the U.S. Fish and Wildlife Service said two more nests have been found.

The bird, one of the rarest members of the wood warbler family, typically makes its home in the northern part of lower Michigan, nesting in stands of young jack pines.

Officials say this marks the first time nests have been found outside Michigan since the 1940s, when nests were discovered in Ontario.

Females have been observed near the nests, which confirms the birds as a breeding species in the state, the Fish and Wildlife Service said.

Matteson said surveys were done as far back as 30 years ago until the 1980s and males were found in western and northwestern Wisconsin. But Matteson said there had not been any documented females until this year.

Breeding season generally lasts for several weeks in June. The birds winter in the Bahamas and return to the Upper Midwest during the warmer months.

Kirtland’s warblers settle only in young jack pine forests of more than 80 acres. They nest on the ground beneath the branches of trees from 4 to 20 years old.

But they’re finding it more difficult to find suitable habitats because of forest fire prevention, which is keeping jack pines alive longer. Since fewer new treats are growing, Kirtland’s warblers find their natural nesting area possibilities reduced, meaning their numbers are declining.

To offset this, Michigan plants or seeds about 3,000 acres of new jack pine trees a year.

Louise Clemency, field supervisor for the U.S. Fish and Wildlife Service in Green Bay, said success found in Wisconsin shows Michigan’s efforts are working.

“It’s great to see that years of intensive protection efforts by the state and federal partners in Michigan are paying off as the growing population there rebounds and spreads out around the region,” Clemency said.

Kirtland’s warblers have been on the endangered species list since 1967. Their population hit a low of 201 males in 1971, dropping from 432 singing males in 1951.

But their numbers now are among the highest recorded, 1,486 males in 2006.

Each male has a distinct song to mark his territory, so male numbers are counted and then often doubled to include females.

The exact locations of the nests are not being released so the birds’ habitat is not disturbed.

But authorities did say the nests were found on property belonging to the Plum Creek Timber Co., which is helping develop conservation efforts in Wisconsin and Michigan for the warblers.

The company is also one of 40 partners with the Fish and Wildlife Service and the DNR to protect the endangered Karner blue butterfly.

The company is always looking to show endangered species can coexist with land and timber companies, said Rob Olszewski, Plum Creek’s vice president of environmental affairs.

The Wisconsin DNR said it hopes to work with landowners to survey more breeding habitat for the birds.