Bioacoustics of Urocitellus armatus

Habitat. Large open meadows at high elevations near timberline. The Uinta Ground Squirrel can inhabit dry meadows and shrub-steppe communities and can be found in agricultural and rangelands. Food and Feeding. The Uinta Ground Squirrel is a generalist herbivore, with grasses comprising most of its diet, but seasonal variation is reported. Immediately following emergence, 90% of the diet consists of grass leaves, but this food component later decreases when leaves of forbs and grass seeds are added. Sagebrush (Artemisia, Asteraceae) leaves, earthworms, and roots are also eaten. They will eat insects and scavenge animaltissue; infanticide and cannibalism have been occasionally reported. Breeding. The Uinta Ground Squirrel inhabits burrows with a vegetation-lined nest chamber in which young are born. Males exhibit territorial behavior soon after emergence and scent-mark by rubbing their cheeks on the ground. Female distribution, however, often causes males to shift territories. Breeding occurs within ¢.30 days of emergence. Aggression between males—fighting, biting, and some vocalizations—is common during breeding season. Females are in estrus for less than one day, usually 2-3 days after emergence from burrows; mating occurs in burrows. Yearling males usually do not mate; yearling females can mate but may experience reproductive failure. The Uinta Ground Squirrel produces only one litter peryear, following a gestation of 23-26 days. Litter sizes are 4-6 young, usually less than initial numbers of embryos. Young are born in the beginning of May and typically emerge c.22 dayslater. After mating, females become aggressive and intolerant until their young are weaned. Activity patterns. Uinta Ground Squirrels are diurnal. They often arouse from hibernation and emerge from burrows in April. Adult males emerge from burrowsfirst, followed adult females 1-3 weekslater and then yearlings appear. Immergence of adults can begin as early as late July, with juveniles entering hibernacula by the end of August. Movements, Home range and Social organization. Uinta Ground Squirrels live in loose colonies. Densities are high as 28 ind/ha. Vocalizations are involved in agonistic behavior, and alarm calls are used to warn of predators. Ground predators elicit a churr call; aerial predators cause distinctly different chirp call. Body mass is better than age to predictlitter size. Juvenile males disperse from colonies; females typically remain philopatric to their natal burrow.