DOE/EIS-0332; McNary-John Day Transmission Line Project Draft ...

3
3-70
Affected Environment, Environmental
Consequences, and Mitigation
Species Risk of Collision
Migratory waterfowl have the highest incidence of mortality from collision with
transmission lines, particularly near wetlands, feeding areas, or open water (Stout 1976).
Such collisions primarily occur in low visibility conditions (Arend 1970, Anderson 1978,
Avery et al. 1980, Brown et al. 1985, Fannes 1987). In a study of waterfowl mortality in
Illinois, between 0.2 and 0.4% of the maximum number of ducks present near a power
plant were killed each fall (Anderson 1978). Mallards and blue-winged teals were found
to be most vulnerable to collisions. Fourteen duck species accounted for 44% of the
4,100 birds that collided with power lines in a wetland in Montana (Malcolm 1982). In a
survey of birds flying past a 138-kV power line spanning the Mississippi, no birds were
killed and waterfowl were observed to fly at least 50 feet from the power lines
(Fredrickson 1983). In a survey in Oregon, 60 birds of 13 species were found dead
beneath a 230-kV line in 89 days; however, an estimated 354,000 birds moved past the
lines in 179 days; of which over 85% were observed to fly above the conductors (Lee
1978). Migratory waterfowl, including mallards and blue-winged teal, use the area along
the proposed line describe above and could be impacted by the addition of the proposed
line.
American white pelicans that feed on islands 3 miles south of Paterson are known to nest
on Crescent Island approximately 20 miles northeast of the project corridor. Mortality
from collision with of pelicans power lines has been reported elsewhere (Brown 1993,
Crivelli 1988).
Raptor collisions with overhead wires would be expected; however, collision with
overhead transmission line wires is not a major cause of mortality in raptors. Raptors
keen eyesight and tendency not to fly in inclement weather may contribute to the
relatively low numbers of collisions reported (Olendorff and Lehman 1986), and
therefore any raptor collisions would not be at levels that would change local breeding
populations or distributions.
Some level of ongoing waterfowl and perhaps raptor and pelican mortality would be
expected to occur as a result of the installation of the new transmission lines, however,
the mitigation measures discussed later in the Mitigation section can be applied to
minimize that potential impact.
Avoidance of Areas by Wildlife
Wildlife may avoid the proposed transmission facilities because of human use such as
maintenance or because of the presence of the structures. Deer would temporarily avoid
areas with human activity, while bird responses to power lines may vary by species. For
example, waterfowl may avoid habitat areas with transmission lines above them (Willard
1982). On the other hand, raptors are often attracted to transmission towers to use them
as nesting sites (Bechard 1990). Other species such as songbirds may be attracted to the
shrub-steppe or grassland vegetation corridors that are undisturbed by agricultural uses or
residential uses occurring in rights-of-ways.
BPA McNary-John Day Transmission Project
Draft EIS
February 2002