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DRAFT DRAFT DRAFT <br />1984). Availability of nests and food supply are considered limiting factors for raptor <br />populations (Whitcomb et al. 1981, Temple 1986, Wilcove et al. 1986, Cline 1988, Watson and <br />Langslow 1989). Raptors compensate for the loss of foraging and nesting habitat by abandoning <br />established territories and/or attempting to utilize less productive or already occupied territories <br />(Nelson 1979, Newton 1979). Other factors affecting raptor distributions and densities include <br />human persecution, exposure to toxic chemicals, diseases, parasites, and predators (Mersmann <br />and Fraser 1988, Newton 1989). <br />Habitat management recommendations should be planned to: <br />Avoid or minimize impacts to habitats which could reduce or change raptor prey <br />populations beyond the natural range of variation. <br />2. Avoid or minimize impacts to habitats preferred by raptors for nest and roost locations. <br />Mitigate for unavoidable habitat losses. <br />Recommendations in the following sections are intended to facilitate project planning efforts in <br />light of regulatory requirements of various wildlife laws and provisions of NEPA. These <br />recommendations are not all-inclusive of available strategies, but provide a framework for land <br />use planners to follow. Project proponents should select from these management <br />recommendations and/or develop other protective measures based on the raptor species, the <br />project and its potential impacts. Generally, project proponents should first avoid impacts to <br />raptors and only then minimize and mitigate unavoidable impacts. Coordination with biologists <br />from the Service, State wildlife resources management agency, and/or the respective land <br />management agency will help ensure that the objectives and recommendations of these <br />guidelines are achieved. The occurrence and habitat requirements of other wildlife species in the <br />area should also be taken into account when selecting and implementing these habitat <br />management plans. <br />Guidelines for Avoiding and Minimizing Impacts <br />Raptor Foraging Habitat <br />A variety of birds, small mammals, reptiles, amphibians, and insects constitute the bulk of the <br />prey base for raptor species (Steenhof 1983, Palmer 1988). Some species will forage on carrion <br />as well as live prey; some are specialists that primarily take fish, while others are generalists <br />(Steenhof 1983). Construction of facilities, transportation infrastructure, power lines, and other <br />actions contributing to habitat loss and fragmentation are often required by many types of <br />industrial development and can directly and indirectly affect diversity, abundance, and <br />availability of raptor prey populations. Road developments in particular have been shown to <br />restrict movements of small mammals and birds which may affect their dispersal and population <br />levels (Oxley et al. 1974). Management and mitigation efforts should be focused on maintaining <br />and improving habitats sufficient to support healthy prey populations. Some raptors such as <br />burrowing owls use human-altered environments and human structures such as culvert drains and