Laserfiche WebLink
DRAFT DRAFT DRAFT <br />4. <br />damage until they become established. Livestock grazing strategies should be <br />developed to en'sure' maintenanee or improvement of raptor nesting/roosting <br />habitat (Need references). <br />b. Trees or snags with existing raptor nests can be stabilized if alternative sites are <br />limited. <br />Rockpiles can be constructed to provide perches and nest sites for some raptor <br />species. Prey species also benefit from the hiding and denning values provided by <br />rockpiles. <br />d. Artificial nest platforms and nest boxes can be constructed for some raptor species <br />to increase potential nesting sites (Millsap et al. 1987). Call (1979) provides <br />appropriate specifications for tree-nesting, cavity nesting, and underground- <br />nesting raptors. Individual artificial nest platform designs are available on a <br />species by species basis for most raptors. <br />Improve existing nest sites. Quality of existing nests may be more important than the <br />quantity in some areas (Millsap et al. 1987). <br />a. Remove excessive accumulations of nest material (primarily for cliff-nesting <br />raptors). Long-term buildup of nest material can bring a nest into reach of a cliff <br />top, increasing accessibility by predators. <br />b. Remove.rocks or other debris which have fallen into nests, rendering them <br />unusable by raptors (primarily for cliff-nesting raptors). <br />C. Reinforce and stabilize trees, snags, and cliff ledges which contain existing nests <br />to perpetuate continued use of these established sites. <br />Direct Mortality within Habitat Use Areas <br />Of 25 types of land-use actions identified by Olendorff et al. 1989, at least 8 (32 percent) of these <br />are known to cause individual raptor mortalities, including: wind energy, roads/railroads, utility <br />lines, fire, mechanical/chemical, illegal harvest, heavy metals, and rodent control <br />agents/pesticides. (Need to discuss these paragraphs-Mig birds thought these were speculative <br />and that there was no real data to support guidelines.) For example, direct mortality of raptors <br />occurs along roadways and railways from collisions with moving vehicles. Raptors foraging <br />along roadside habitats or on road-killed carcasses increase the potential for raptor-vehicle <br />collisions. (The rest of this paragraph and the next one are focused on Utah examples-do we <br />want to pare down and include examples from other states to truly make this regional?) <br />For instance, in a two-year study, 26 observations were made of young ferruginous hawks eating <br />dead jackrabbits on roads in northern Utah and southern Idaho (Howard 1975). Road-killed <br />jackrabbits have also been identified as a primary food source for bald eagles wintering in Utah <br />(Platt 1976). Traffic collisions are a significant factor of mortality for many species of owls and <br />13