The U.S. Fish and Wildlife Service said the rate of logging of old growth forests in the Pacific Northwest threatens the existence of the northern spotted owls. Federal biologists also said Wednesday that plans developed by the U.S Forest Service and the Bureau of Land Management to protect the owls are untested and may not work. At news briefing, the Wildlife Service released a court-ordered re-evaluation of the tiny owls, which have become the focus of a raging environmental dispute between conservation groups and the timber industry. The agency submitted findings to U.S. District Judge Thomas Zilly in Seattle that recommend the owl be listed as a threatened species.