In a blow to environmentalists, the California spotted owl has been denied protection under the federal Endangered Species Act. According to the U.S. Fish and Wild Service, there is not enough evidence that the owl’s habitat is sufficiently threatened to merit listing — even though the agency acknowledged that a U.S. Forest Service plan to increase logging in the Sierra Nevadas could compromise the bird’s habitat. Enviros said yesterday’s decision by the USFWS represented the sixth time in as many weeks that the agency had denied a species endangered status. (Five of the six rejected species, including the owl, live in California.) Some organizations have already sued to overturn the decision.