Life History and Habitat Requirements. The Amargosa vole is a xxxxx-bodied, almost cylindrical, compact rodent. The comparatively short tail, small rounded ears, and short legs easily distinguish it from most other small, mouse- like rodents. The Amargosa vole averages 8 inches in length, with an average tail length of 2.5 inches. Xxxxxxxx et al. (2018) observed sexual dimorphism in Amargosa voles, finding that males had significantly larger body mass, longer total length and longer tail length. Coloration is “bright” xxxxx, ranging from cinnamon buff to “buckthorn” xxxxx (Xxxxxxx 1918). Distinguishing characteristics include the “bright” pelage coloration and a small skull with comparatively large zygomatic width (Xxxxxxx 1918). Amargosa voles may be active throughout the year, during both day and night, although they seem to be largely crepuscular (Madison 1985). Microtus subspecies (collectively) generally consume grasses, forbs, and seeds (Heske et al. 1984). Grasses in the genera Hordeum, Bromus, and Lolium were identified as food items in a central California vole population (Xxxx 1977). When seasonally available, green emergent vegetation comprises the bulk of the diet; grass seeds are most common in the diet during the summer and autumn (Batzli and Pitelka 1971). Microtus subspecies are primary consumers and are often the principal herbivores within occupied habitats (Rose and Birney 1985). Amargosa voles have been reported to be dietary specialists on Olney’s three-square bulrush; however, they have been observed on camera eating other plants within marshes, have been found with components of multiple plant species in their feces, and under various circumstances have been observed feeding on a variety of plant and insect foods while in captivity (Castle et al. in press). Microtus subspecies generally excavate an extensive underground network of runways and tunnels (Xxxxx 1985), and in dense cover frequently develop extensive surface runways (Xxxxx and Xxxxx 1985). Amargosa voles do most of this excavation within the dense litter layer of Olney’s three-square bulrush found in marshes. Microtus subspecies generally lack physiological or morphological characteristics necessary to tolerate high temperatures (Rose and Birney 1985), and their inability to concentrate urine and conserve water are major reasons for their distributional restriction to mesic and wetland habitats (Xxxx 1985); for example, California voles (Microtus californicus) require regular intake of large amounts of water, m...
Life History and Habitat Requirements. The NSO is one of three spotted owl subspecies, with the California and Mexican spotted owls generally occuring further south. NSO are nocturnal and prey predominantly on small mammals, primarily northern flying squirrels (Glaucomys sabrinus), bushy-tailed woodrats (Neotoma cinerea), and dusky-footed woodrats (N. fuscipes). The NSO is a territorial raptor that ranges widely in search of prey and has an estimated home range size that varies from 2,955 acres in the Oregon Cascades (Xxxxxx et al. 1990) to 14,211 acres on the Olympic Peninsula (USDI FWS 1994). NSO are central-place foragers (Xxxxxxxxx and XxXxxxxx 1999) and typically concentrate their use within a 500 acre area called the core that surrounds the nest site and favored foraging areas (Xxxxxxx and Noon 1997, USDI FWS 2009). An NSO activity center is defined as the location or point representing a nest stand, including forested stands used by roosting pairs or territorial singles, or concentrated nighttime detections. Activity centers are found within the core use area and are represented by this central location (USDI FWS 2012a). Throughout its range, NSO are associated with older conifer and mixed-conifer forest that contain structures and characteristics required for nesting, roosting, and foraging. Features that support nesting and roosting typically include a multilayered, multispecies canopy dominated by large [greater than 30 inch diameter at breast height (DBH)] conifer overstory trees and an understory of shade-tolerant conifers or hardwoods; a moderate to high (60-80 percent) amount of canopy closure; substantial decadence in the form of large, live coniferous trees with deformities; numerous large snags; ground cover characterized by large accumulations of logs and other woody debris; and sufficient open space to allow flight under the canopy (Xxxxxx et al. 1990). NSO do not build their own nests and depend on existing structures such as cavities, platforms formed by mistletoe infections, and broken tree tops for nesting. Forests containing older, larger-diameter, deformed, decadent, or diseased trees provide these suitable nest structures. Large diameter snags provide cavities and platforms for nesting, and coarse woody debris on the forest floor and snags provide habitat for the small mammal species that NSO select as prey. Compared to younger, open forests, older dense forests provide better thermal and escape cover for NSO in the form of a more moderate, stable microclimate and be...
Life History and Habitat Requirements. The xxxx wolf is not associated with a particular habitat type. Wolf habitat ranges from open grassland to thick conifer forests to high alpine tundra. Wolves require an adequate food supply, suitable xxxxxxx and rendezvous sites, and travel corridors. Its diet can be varied, ranging in size from ground squirrels to bison (Xxxxxxxx and Xxxxxx 2003). Ungulates, such as caribou, deer, elk, and moose, represent most of the biomass consumed (Xxxxxxx et al. 1987, Xxxxxx 1989a, Xxxxx 1998, Xxxxxxxx and Xxxxxx 2003, Xxxxxxxx et al. 2004). Wolves in California are expected to prey mostly on Roosevelt elk (Cervus canadensis roosevelti) and black-tailed deer (Odocoileus hemionus columbianus) in the northwestern part of the state and on Rocky Mountain elk (Cervus Canadensis nelsoni) and mule deer (Odocoileus hemionus) in northeastern California (Xxxxxx et al. 2016). Wolves tend to avoid areas with large amounts of human habitation and disturbance (Xxxxx 1985, Mech 1988, Mech et al. 1988). A wolf pack’s territory commonly encompasses 100-220 square miles to include ungulate winter and summer range, but can extend up to 1,000 square miles depending on habitat type and prey abundance (CDFG 2011, ODFW 2015). Most xxxx xxxx packs, even those that include two or more adult females, produce only a single litter of pups each year (Xxxxxxxxxx et al. 1982, Packard et al. 1983), although occasional multiple litters have been reported (Xxxxx 1944, Xxxxxxx et al. 1987, Mech et al. 1998). Pups are born in early spring with an average litter size of six (Gavrin and Donaurov 1954, Mech 1970, Hayssen et al. 1993). Dens are excavated as early as fall (Xxxxx et al. 1997) and tend to be centrally located within the territory (Xxxxxxx and Dau 1983, Xxxxxx 1989b). Den characteristics vary by location and availability of adequate sites, but most tend to be located near water to meet the lactation needs of nursing females (Mech 1970, Packard 2003). A den can occur in a rock crevice, hollow log, or under the roots of trees (Mech et al. 1998). Home ranges may contain several dens, each of which may or may not be reused across years (Xxxxxxx and Dau 1983, Mech et al. 1998). After six to ten weeks, pups are moved from the dens to rendezvous or post-xxxxxxx sites. Rendezvous sites are occupied by wolves during the summer and early fall months and are used for resting, feeding, and other activities (Xxxxxxxx and Boss 1981). These sites usually include small (i.e., one acre or less), secluded bogs...
