The U.S. Fish and Wildlife Service is proposing to take the gray wolf off the endangered species list. The wolf had been extirpated from the West and had dwindled most other places in the U.S. The great canine has rebounded since it was reintroduced to the northern Rockies in the 1990s and is continuing to spread into the Pacific Northwest. But biologists warn that if these wolves loses federal protection, they will not be able to return to some places, such as Colorado, where the ecosystem sorely needs them.