Eastern Chipmunk

activity

Activity patterns. The Eastern Chipmunk is terrestrial and diurnal, with an activity peak in the middle of the day, although activity patterns of males and females may differ. In the period between late autumn and early spring, most individuals are underground at different levels of torpor, but some individuals may emerge at surface when weather is favorable. Body temperature is usually 36 ° C — 40 - 3 ° C at ambient temperatures of 7 ° to 32 ° C, but can be severely reduced during torpor bouts. Torpor bouts are short, usually lasting 1 - 5 days, and the main energy reserve is food stored in a larder. Compared to otherspecies, the Eastern Chipmunk has a very small fat reserve. When quality of food in larder increases, individuals tend to reduce depth and duration of torpor bouts. During summer, activity of the Eastern Chipmunk is also reduced, although the cause of this phenomenon is unclear. Summer activity reduction may be a physiological or behavioral adaptation, or perhaps both; however, food supplementation did not appear to affect summer activity levels.

Sciuridae

biology_ecology

Habitat. Deciduous Forest. The Eastern Chipmunk occurs in a large variety of habitats; its presence and abundance are related to availability of mast producing trees, especially oaks (mostly white oaks Quercus alba, Fagaceae) and red maples (Acer rubrum, Sapindaceae) in some areas. Availability of cover, such as woody debris, stumps, downed trees, and potential burrows also affects its abundance. The Eastern Chipmunk is usually more abundant in mature forests, but survives well in fragmented landscapes and is able to cross open clear-cuts of ¢. 250 m or more. At least one study found little difference in its abundance in northern hardwood stands from sapling age to mature forest. Microhabitat around burrows is reported to be similar in continuous and fragmented forests.

Sciuridae

biology_ecology

Movements, Home range and Social organization. The Eastern Chipmunk is solitary and territorial, defending an area within a 15 m radius around its burrow system, but most encounters are stereotypic displays and real agonistic encounters are rare. It is a very vocal species, with four different calls, with frequency ranging 1 - 11 kHz. It usually responds to neighbor calls by sitting and observing the area for possible threats. Home ranges are usually small, 0 - 05 - 0 - 6 ha, but vary according to season and across the distribution of the species. The Eastern Chipmunk may also go farther than 100 m from burrow to collect food, and is capable of returning to its burrow from distances as far as 500 m, although the probability of a successful return is reduced after 200 m. Home range appearsto be related to food availability. It can live up to c. 6 years, but life span is usually 2 - 3 years. Population density is extremely variable over time and space, ranging 0 - 3 - 37 - 6 ind / ha. There is contrasting evidence as to whether density is affected by habitat fragmentation.

Sciuridae

breeding

Breeding. The Eastern Chipmunk has two mating periods in the year, the first one between late February and early April, and the second in late June-July. Females can reproduce in one of the periods or in both, resulting in two litters a year. Estrus is estimated to last from 6 - 5 hours to ten days. During this period, several males pursue a female, and mating success of dominant male is usually high when there are few competitors, but subordinates have a better chance at mating success when there are many competitors. Dominant males can mate several times, and females can also mate with several males. Gestation lasts ¢. 31 - 32 days after which females give birth to a litter of 4 - 5 young, with 15 being maximum recorded, weighing c. 3 g each at birth (range 2 - 5 - 5 g.). Young have an adult-like coloration at one month of age. Emergence from natal burrow occurs at 5 - 7 weeks, and sexual maturity is reached at 7 - 8 months (males) or c ¢. 3 months (females), although reproduction before the first winter is rare. Males and females disperse from natal area, but males tend to go farther than females, possibly reducing inbreeding and mate competition.

Sciuridae