GRANTS PASS, Ore. — The Bush administration is working on a new plan for removing Endangered Species Act protections for thriving populations of gray wolves in the Great Lakes and Northern Rockies after deciding not to fight a federal court ruling that found the old plan illegal.

Assistant Interior Secretary Craig Manson, in a statement released Tuesday in Washington, D.C., said he continued to believe the old plan was "biologically and legally sound" — but the Department of the Interior would be issuing a new proposal "as early as possible in 2006."

Michael Robinson of the Center for Biological Diversity, a plaintiff in the case, said the center would not oppose removing Endangered Species Act protections for wolves introduced in Idaho and Yellowstone National Park, or those naturally occurring in northern Minnesota, Michigan and Wisconsin — as long as the Bush administration does not try to "gerrymander" the population boundaries again.

"We agree there's a robust population in the Great Lakes states and there is a robust population of wolves in the Northern Rocky Mountains," said Robinson.

"We support the goal of delisting populations that are recovered," he added. "What we don't want is areas outside the areas where wolves have recovered to have protections removed in the process of delisting these robust populations. That's why where the lines are drawn is so crucial."

Last February, U.S. District Judge Robert E. Jones in Portland ruled that Interior Secretary Gale Norton had improperly applied the policy for designating distinct population segments under the Endangered Species Act by extending the boundaries from thriving populations in the Northern Rockies and western Great Lakes to include vast areas of the West and East where the wolves are just hanging on or are extinct.

As a result, the status of populations within the Western population, for example, varied dramatically, from recovered in parts of Montana, to precarious in Washington, to extinct in Nevada, the judge ruled.

The judge also found the U.S. Fish and Wildlife Service did not consider five factors listed in the Endangered Species Act in evaluating the wolf's status across its range: the state of habitat; over-exploitation for commercial, recreational, scientific or educational purposes; threats from disease and predators; the inadequacy of existing regulations; and other natural or man-made factors affecting survival.

The ruling effectively maintained endangered species status for wolves moving into states such as Oregon and Colorado from Idaho and Montana, so that states could not authorize ranchers to shoot wolves that attacked their livestock. By downgrading those migrating wolves to threatened species status, the Bush administration plan would have allowed ranchers to kill wolves attacking livestock.