Movements of intercolony natal dispersers in the Columbian ground squirrel

Abstract

Eight yearling male Columbian ground squirrels (Spermophilus columbianus) were radio-collared in an attempt to document emigration from an isolated montane meadow in southwestern Alberta. Six of the eight squirrels emigrated from the meadow over a 14-day period. All six dispersers departed during the first half of the day, before 13:30. Four of the squirrels were known to have travelled briefly in and out of the forest habitat bordering the meadow before emigrating, possibly searching for exit routes. During emigration, squirrels moved quickly (up to 4.0 km/h) over relatively long distances, stopping occasionally for extended periods of time [Formula: see text]. Emigrating squirrels followed cutbanks along natural drainages, roads, and game trails; routes tended to interconnect patches of suitable ground squirrel habitat. While dispersing, five of the six emigrants were known to have encountered such patches within 10 km of the natal colony. None of the squirrels died while being tracked and four squirrels were known to have settled either temporarily (two) or permanently (two) in patches of suitable habitat. The latter settled permanently in meadows where other animals were present and the former in meadows without resident squirrels but where refuges (artificial burrows or log piles) had been provided.