![]() ![]() Alarm signals are multi-syllabic and use variation in acoustic structure and repetition to convey predator class and response urgency to listening colony members. This species exhibits complex, apparently altruistic alarm vocalizations. ( Michener and Koeppl, 1985 Michener, 1979a Schmutz, et al., 1979 Yeaton, 1972) Communication and Perception For males, their home range is smallest after the breeding season, increase in size in midsummer, and is once again reduced just prior to hibernation. Female home ranges are constrained near the burrow over the period of gestation and lactation, expand after natal emergence, and are once again reduced during the four weeks preceding hibernation. Both males and females undergo seasonal variation in their home range size. Female home ranges are usually smaller than males because of dispersal, however in years where female home ranges are larger, female movements can be more widespread than years where the range of male dispersal is constrained. The range and movements of male dispersal remain poorly understood, however movements of 3 to 10 km from the natal site have been observed. ( Davis, 1984b Michener and Koeppl, 1985 Michener and Michener, 1977 Michener, 1973c Michener, 1979a Michener, 1980a Quanstrom, 1971) Dispersing juvenile males leave during this phase, and interaction becomes increasingly infrequent (although interactions between siblings remain amicable) as spatial dispersion increases. Juveniles establish their distinct core area near their family, however they no longer share their burrow with littermates or their mother. The third and final phase before hibernation is characterized by a reduction in adult squirrels' range and time spent above ground. ( Davis, 1984b Michener and Koeppl, 1985 Michener and Michener, 1973 Michener, 1973c Michener, 1979a Michener, 1980a Quanstrom, 1971) Social interactions between juveniles and their mother or littermates are amicable, however interactions with more distantly related and unrelated individuals tend to be antagonistic. Two weeks after emergence, juveniles begin to interact with other neighboring adults and juveniles from other litters. The spatial distribution is highly aggregated at this time, with densities as high as 56.3 juveniles/ha on a 2 ha site. The next phase is 4 weeks and begins at the time of natal emergence as juveniles gradually expand their range from the natal burrow. It is during this phase that each female excavates her burrow, makes a nest, and rears her litter in isolation. At this time, females exhibit site-dependent dominance and are aggressive to conspecifics, particularly males and distantly related or unrelated females. ![]() For the 7 week pregnancy and lactation phase, females are evenly dispersed in core areas that overlap slightly with related neighbours. Richardson's ground squirrels have three major phases in their spatial and social patterns after the mating period. ( Michener and Koeppl, 1985 Michener and Michener, 1977 Michener, 1973b Michener, 1979a Michener, 1979b Schmutz, et al., 1979 Yeaton, 1972) Smaller study sites have found 12.0, 19.1 and even 27.0 adults/ha. Surveys on a 108 ha site found clusters of 5.3 adults/ha over a single 1.5 ha portion, while the overall density for the site was 1.5 adults/ha. This species thrives in anthropogenic altered habitats such as pastures and ploughed fields, favoring regions with short grass ( 10 ha) sites ranging from 1.4 to 5.2 individuals/ha during peak mating season. The species is semi-fossorial, digging extensive burrow networks, consisting of chambers, passages and numerous entrances. Richardson’s ground squirrels inhabit grasslands, fields, rolling hills and farmlands. ( Michener and Koeppl, 1985 Swenson, 1981) ![]() As Richardson's ground squirrels are non-migratory, their range is seasonally stable. In the United States, the species range spans western Minnesota, North Dakota, north-eastern South Dakota and northern Montana. Richardson's ground squirrels are a native northern plains species found in Canada through foothills of the Rocky Mountains in southern Alberta, southern Saskatchewan, and southwest Manitoba. ![]()
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