Abert's Squirrel

activity

Activity patterns. Abert’s Squirrels are diurnal and active throughout the year. They have bimodal activity summer with peak activity in the early morning and late afternoon; activity in winter tends to be unimodal and centered on midday heat.

Sciuridae

biology_ecology

Habitat. Forests dominated by pines (Pinus, Pinaceae) and are often suggested to be obligates of ponderosa pine (Pinus ponderosa) forests. Mosaic, heterogeneous, and Abert’s Squirrels typically use areas of dense growth in favored unevenly aged forests. Recent evidence suggests that it can persist in more diverse coniferous forests.

Sciuridae

biology_ecology

Movements, Home range and Social organization. Abert’s Squirrel constructs spherical dreys of pine needles, leaves, and twigs and also den in tree cavities. Individuals live and forage alone, only occasionally interacting with others at concentrated food sources. Communal nesting is uncommon but does occur particularly in winter. Dense growth of twigs known as witch’s brooms caused by parasitic mistletoes are commonly used to anchor and obscure nests. Nests are located in larger and taller trees with canopies connected to adjacent trees and are found in more dense stands of trees, rather than being situated at random in the surrounding area. Individuals change nests regularly and maintain several active nests simultaneously. Foraging occurs in all canopy levels, with significant time spent on the ground. Home ranges are relatively large, often greater than 20 ha, with male ranges larger or equivalent to those of females, perhaps due to mate searching. Abert’s Squirrels rarely vocalize, but when threatened, they utter an alarm call of low frequency and short series of chatters and chucks that has been compared to the bark of a poodle.

Sciuridae

breeding

Breeding. Abert’s Squirrel breeds in spring or early summer when females are receptive for a single day and up to ten males pursue the female. Males possess scrotal testes in winter through summer, after which testes are withdrawn into the abdominalcavity. Females mate with multiple males and solicit copulations from some low-ranking males. Females produce single litters of 2 - 6 young each year, typically in late spring or early summer, after gestation of ¢. 46 days. Dreys and nest cavities are used to rear young. Females may produce a second litter in some localities. Young remain with their mother until natal dispersal, at c. 10 weeks of age. Most individuals are able to reproduce at one year old.

Sciuridae