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Rapror Survey Report for the Lorencito Coal Company Property Results No raptors were observed and no raptor nests were noticed during the five hours of the survey within the permit area. Very few bird species were observed during the survey. Discussion . The accuracy and success of a raptor survey is determined by the ability to detect the individual raptors. Detection ability differs by raptor species due to body size, habits (e.g., soaring, perching high or low in vegetation), and the preferred habitat's structure (i.e., open grassland vs. pinyon pine forest) (Craig 1978, Craighead and Craighead 1956, Diesel 1984, Marion and Ryder 1975). These authors estimated that between 2 and 92 percent of actually occurring raptors were observed during road surveys. The lack of observed raptors and their nests during the 2002 spring raptor survey, therefore, does not indicate that raptors aze not present in the permit area. The pinyon pine and juniper habitat, as well as the geographical location, is suitable for a large number of raptor species. The Lorencito Canyon Mine permit report noted 26 species of raptors indicated by the Colorado Division of Wildlife as potentially occurring within the general vicinity of the property, including vultures, owls, hawks, falcons, and eagles. The previous raptor survey, performed in 1996 as part of the mine permit application process, noted only four species of raptors within the permit area. The previous raptor survey did not observe any raptor nests within the permit azea, but did observe raptor nests in the portion of the property south of the permit area. The previous raptor survey was conducted over several days by more than one biologist, and included other techniques besides a road survey. Literature Cited Craig, T.H. 1978. A car survey of raptors in southeastern Idaho. 1974-76. Raptor Research 12:40-45. Craighead, J.J. and F.C. Craighead. 1956. Hawks, owls, and wildlife. Stackpole Co., Harrisburg, Pennsylvania. 443 pages. Diesel, D.A. 1984. Evaluation of the road survey technique in determining flight activity ofred- tailedhawks. Wilson Bulletin 96:315-318. Fuller, M.R. and J.A. Mosher. 1987. Raptor survey techniques. Pages 43-65 in B.A.G. Pendleton, B.A. Millsap, K.W. Cline, and D.M. Bird, editors. Raptor Management Techniques Manual. National Wildlife Federation, Washington, DC. Marion, W.R, and R.A. Ryder. 1975. Perch-site preferences of four diurnal raptors in northeastern Colorado. Condor 77:350-352. Lorencito Coal raptor survey rpt.tloc 08/28/02