Draft Environmental Impact Statement for Roca Honda Mine

Chapter 3. Affected Environment and Environmental Consequences
The following Forest Service sensitive species are found within the permit area or have the
potential to occur within the permit area: American peregrine falcon, gray vireo, Merriam’s
shrew, spotted bat, Pale Townsend’s big-eared bat, Gunninson’s prairie dog, Western burrowing
owl, Botta’s pocket gopher, clam shrimp, and fairy shrimp. The American peregrine falcon, gray
vireo, and spotted bat are discussed above. The remaining species or their habitats do not occur
and will not be considered further for this proposed project.
In New Mexico, western burrowing owls inhabit grasslands, open shrublands, and woodlands at
lower to middle elevations (2,800–7,500 feet). These owls occupy nonriparian habitats
exclusively or nearly so during the breeding season. Arthropods (beetles, grasshoppers, and
crickets) form the majority of their diet. They use abandoned burrows of ground squirrels, prairie
dogs, and other burrowing mammals for nest sites. Limiting factors include decreasing numbers
of burrow-digging mammals, avian and mammalian predators, starvation, diseases and parasites,
and poisoning (resulting from human efforts to control squirrels and prairie dogs). Optimum
habitat is typified by shortgrass vegetation and presence of fresh small mammal burrows,
especially prairie dogs.
The Gunnison’s prairie dog is known to occur within the permit area and at least four small to
large prairie dog towns were observed during wildlife surveys (RHR, 2011a). Habitat of
Gunnison’s prairie dog includes grassland/herbaceous and shrubland/chaparral vegetation. This
species is found in high mountain valleys and plateaus between elevations of approximately 6,000
and 9,000 feet, open or slightly brushy country, and scattered junipers and pines (NatureServe,
2010d). In New Mexico they are found in level to gently sloping grasslands, semidesert and
montane shrublands between 7,000 and 8,500 feet (RHR, 2009d). Their diet includes grasses,
forbs, sedges, shrubs, and insects. Individuals have some periods of inactivity during winter,
potentially lasting several months. During the prairie dogs’ active months—spring and summer—
they are active during the early morning and late afternoon. Populations throughout its range have
declined significantly from historic levels. The main threat to the prairie dog is the sylvatic
plague. Sylvatic plague is a bacterial disease generally transmitted among rodents by fleas and is
often fatal. Other threats include poisoning and climate change in the montane portion of their
range (NatureServe, 2010d).
Merriam’s shrew is not known to occur in the permit area and was not observed during wildlife
surveys, but piñon -juniper is considered suitable habitat. This is one of the least known of all the
shrew species. It is extremely rare, with hundreds of pitfall trap/baited small mammal trap hours
needed to capture one individual. In addition the species is extremely difficult to identify and only
close, microscopic examination of the teeth will allow experts to identify it with certainty (USFS,
2009d).
Pale Townsend’s big-eared bat is not known to occur in the permit area and was not observed
during wildlife surveys, but suitable habitat does exist within the permit area. This bat is a
western species occurring in semidesert shrublands, piñon-juniper woodlands, and open montane
forests, including spruce-fir. It is associated with caves and abandoned mines for day roosts and
hibernacula, but will also use abandoned buildings and crevices on rock cliffs for refuge.
Maternity sites include trees, caves, or manmade structures. They do not move long distances
from hibernacula to summer roosts nor do they forage far from their day roosts. Their diets
consist of greater than 90 percent moths. Threats include habitat loss, cave vandalism, and
disturbance by cave explorers at maternity and hibernation roosts (USFS, 2009d).
220 DEIS for Roca Honda Mine, Cibola National Forest