Pursuant to the Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978, the U.S. Department of Energy (DOE) is proposing to conduct remedial action to clean up the residual radioactive materials (RRM) at the Naturita uranium processing site in Colorado. The Naturita site is in Montrose County, Colorado, and is approximately 2 miles (mi) (3 kilometer [km]) from the unincorporated town of Naturita. The proposed remedial action is to remove the RRM from the Naturita site to the Upper Burbank Quarry at the Uravan disposal site. To address the potential impacts of the remedial action on threatened and endangered species, the DOE prepared this biological assessment. Informal consultations with the U.S. Department of the Interior, Fish and Wildlife Service (FWS) were initiated in 1986, and the FWS provided a list of the threatened and endangered species that may occur in the Naturita study area. This list was updated by two FWS letters in 1988 and by verbal communication in 1990. A biological assessment was included in the environmental assessment (EA) of the proposed remedial action that was prepared in 1990. This EA addressed the impacts of moving the Naturita RRM to the Dry Flats disposal site. In 1993, the design for the Dry Flats disposal alternative was changed. The FWS was again consulted in 1993 and provided a new list of threatened and endangered species that may occur in the Naturita study area. The Naturita EA and the biological assessment were revised in response to these changes. In 1994, remedial action was delayed because an alternate disposal site was being considered. The DOE decided to move the FIRM at the Naturita site to the Upper Burbank Quarry at the Uravan site. Due to this delay, the FWS was consulted in 1995 and a list of threatened and endangered species was provided. This biological assessment is a revision of the assessment attached to the Naturita EA and addresses moving the Naturita RRM to the Upper Burbank Quarry disposal site.