More than three dozen scientists have signed a letter to protest a new Bush administration interpretation of the Endangered Species Act, saying it jeopardizes animals such as wolves and grizzly bears.

The new reading of the law proposed by Interior Department Solicitor David Bernhardt would enable the U.S. Fish and Wildlife Service to protect animals and plants only where they are battling for survival. The agency wouldn't have to protect them where they're in good shape.

The proposed changes would "have real and profoundly detrimental impacts on the conservation of many species and the habitat upon which they depend," said the letter, signed by 38 prominent wildlife biologists and environmental ethics specialists.

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It was being sent this week to Interior Secretary Dirk Kempthorne and leaders of congressional committees that oversee the department.

The scientists wrote that the proposal would have allowed the bald eagle to become extinct in the lower 48 states.

The new policy would give the department an excuse to avoid adding new species to the list, increasing the likelihood of extinctions, said Michael Nelson, an environmental ethicist at Michigan State University.

Nelson and John Vucetich, a wildlife biologist at Michigan Technological University, circulated the letter.

Interior spokesman Hugh Vickery said senior career biologists who run the program are supportive of the proposal and believe it will enable them to "focus their limited resources on areas where species are truly threatened or endangered."

Vickery said it was unclear how the revised policy would affect particular species but accused the critics of exaggerating.

He dismissed as "complete nonsense" the suggestion it would have doomed the bald eagle everywhere but Alaska if it had been in effect decades ago.

Bernhardt's legal analysis was released in mid-March. He said the department needed to reconsider its definition of "endangered" because federal judges had rejected its previous reading of the law in eight of 10 cases since 2000.

Those rulings came after environmentalist groups sued the wildlife service for refusing to add species such as the flat-tailed horned lizard and Florida black bear to the endangered list.

The debate centers on a provision in the Endangered Species Act of 1973 requiring the government to list any plant or animal "in danger of extinction throughout all or a significant portion of its range."

Bernhardt disagreed with court rulings that "range" includes areas where species lived previously but are gone because of habitat loss or other reasons. What matters, he said, is whether they're declining in areas they now occupy.

Bernhardt's definition of "range" would allow the department to settle for keeping remnants of a species intact somewhere, but wouldn't have to return them where people drove them out, Vucetich said.