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Potential of the Hogback Mine for Raptor Nesting Habitat On February 5 1985, I accompanied Eldie Mustard and Randx Hardzog of the Soil Conservation Service on an inspection tour of the Robinson Brick Company's Hogback Mine to determine the potential for establishing raptor nests on the high wall which will remain after excavation. After we visited the site we met with Mike Hissen of Robinson Brick Co: who explained restoration plans for the mine. Following are my recommendations as to actions which might be undertaken to induce occupancy by raptors. - In order to attract nesting raptors the high wall must meet the following criteria: -It must be outside the territories of adjacent raptors; -It must be adjacent to suitable hunting habitat; -It must offer sufficient dominance to the surrounding terrain to serve as a magnet to attract nesting raptors; and -It must offer suitable sites (ledges or potholes) on which raptors can nest. The species most likely to occupy a cliff nest site in this region are golden eagles. prairie falcons, red-tailed hawks and great horned owls. The high wall is probably not extensive enough to be occupied by more than 1 pair of one of the above species. The exception is great horned owls which may nest on the same escarpment if a nest ledge is created specifically for them at a distance from other nests. Generally, the owls prefer deep potholes or crevasses which shield them from direct sunlight. If the owls are not disturbed and flushed during daylight, they will not be attacked by the adjacent nesting diurnal raptors. . With regard to the first criterion, the mine high wall is almost equidistant between Martin Marietta to the north on which a pair of golden eagles have nested in the past, "and Roxborough Park to the south which harbors a pair of nesting golden eagles and 1 to 2 pairs of breeding prairie falcons. Golden eagles and prairie falcons have been documented breeding at closer intervals and the high wall is visually isolated sufficiently from the existing wild nest sites to permit an additional pair of either species to establish a territory at the mine. Thus, it is possible that additional cliff nesting habitat may attract a pair of golden eagles, red-tailed hawks or a pair of prairie falcons. It is impossible to establish if suitable unutilized hunting habitat exists adjacent to the site. Since prairie falcons and golden eagles will easily travel 10 miles to hunt, I suspect that sufficient habitat exists to the east and the west to support an additional pair. Although approximately 100 feet of sandstone is exposed at sector i3, the high wall does not possess the dominance that I would prefer. The wall is not perpendicular, but inclines slightly to the west and only the upper portion of the wall is perpendicular at sector Y3. While the wall is inclined backward, it appears to be sufficiently steep to discourage attempted access by mammalian predators, so the nest ledges should be secure. In order to increase the dominance, the overburden should not be pushed up against its base as would be a normal part of the reclaimation effort. In fact, it would be helpful to excavate more material at sector I3 in order to increase the height of the face.