Male Richardson's ground squirrels, territoriality, variability and sociality
- Ecology Division, DSIR, Goddards Lane, Havelock North, New Zealand
[Abstract of a paper read at the Ecological Society Conference, 1983.]
Twenty adult male Richardson's ground squirrels (Spermophilus richardsonii) were observed at two localities in Alberta, Canada. Most males (78–85%) emerged from hibernation before the first female appeared. Males were territorial in those areas where females emerged synchronously. By contrast, males were non- territorial where emergence of females was asynchronous due to the persistence of snow cover, producing a sparse distribution of females. Territorial males tended to be heavier, more dominant, and spend more time alert and less time feeding than did non-territorial males. Dispersal by males occurred before their first hibernation (juveniles), following vernal emergence (yearlings), or following the breeding period (adults). However, some males continued to reside in the areas they had occupied during the breeding period, and in successive breeding seasons adult males were found in the same general vicinity. The mating system of Richardson's ground squirrels resembles that of the more social ground squirrel species, such as Columbian and Arctic ground squirrels.