Laserfiche WebLink
long-distance travels. Corridors also provide cover from predators (e.g., hawks and <br /> falcons) that often follow migrating songbirds. Corridors are essential for the survival of <br /> secretive species that do not readily cross gaps in vegetation. <br /> As habitat corridors become farther and farther apart,migrant birds,particularly songbirds, <br /> must fly longer distances to find cover and food. Longer flights mean longer exposure to <br /> inclement weather conditions and predators,thus reducing migration efficiency. Such <br /> reduced efficiency can result in higher mortality , as migration is the most energetically <br /> demanding period a bird endures. <br /> Corridors are also important in maintaining overall biodiversity. It has been well- <br /> documented that as continuous tracts of forest become increasingly fragmented,carrying <br /> capacity (the number of species and individuals supported by a given area)is reduced <br /> (Whitcomb,gt Al. 1977). Studies have also shown that bird species richness increases as <br /> forest width increases (Stauffer and Best 1980). In essence,one can look at fragmented <br /> patches of forest as islands, with smaller islands resulting in less biodiversity. As these <br /> islands become farther apart, travel becomes more limited. If a forest patch were to die <br /> from disease, the organisms living within,if unable to find another suitable nearby patch, <br /> would perish as well. The maintenance of continuous corridors alternatively minimizes the <br /> creation of habitat islands and maintain diversity (Geibert 1980). <br /> Corridors themselves can become traps. The width of a corridor is a critical consideration <br /> in any environmental plans involving corridors. If these avenues of habitat are too narrow, <br /> they become pathways for predators to easily find prey. This is especially true for bird and <br /> mammal species nesting and breeding in narrow corridors, such as passerines in the <br /> Sacramento area which are effectively become more susceptible to predation by small <br /> mammals, hawks,jays (eggs and young), and cowbirds (nest parasitism) (Gaines 1977). <br /> Buckeye Ranch Resource Plan (November, 1993) <br /> 216 <br />