Wolves would remain federally protected in Wyoming because the state's law and management plans were not strong enough, he said. But management of the predator will be turned over to state agencies in Montana, Idaho, Michigan, Minnesota and Wisconsin, and parts of Washington, Oregon and Utah.

The Obama administration had ordered a review of the decision, which was made by the Bush administration shortly before its departure. Salazar said he concluded that dropping the wolf from the list was justified by the species's strong comeback in the two regions, which together have a population of nearly 5,600 wolves.

"The recovery of the gray wolf throughout significant portions of its historic range is one of the great success stories of the Endangered Species Act," Salazar said in a conference call from Washington.

Wolves elsewhere in the Lower 48 states remain on the endangered list.

Courts have overturned previous attempts to remove the wolf from the list, and future legal battles appear likely.

Environmental groups immediately pledged a lawsuit over the estimated 1,500 wolves in the northern Rockies. A federal judge in Missoula, Mont., last year sided with the groups after they filed a lawsuit saying the animal's long-term survival remained at risk, particularly in Wyoming.

The government in January came back with its plan to exclude Wyoming from its decision.

"Whether it's [Bush's Interior Secretary Dirk] Kempthorne or Secretary Salazar, the concern remains the same," said Jamie Rappaport Clark, executive vice president of Defenders of Wildlife and a former Fish and Wildlife Service director under President Bill Clinton. "It's the same plan that I fear doesn't protect the wolf's long-term sustainability."