2002 Franklin Ground Squirrel Summary
Approximately 20 adult Franklinís ground squirrels (9 males, 11 females) occupied the Barnhart Prairie during the summer of 2002.† This figure was obtained from trapping that was limited to April and May.† It is likely that this number fluctuated somewhat throughout the remainder of the summer due to individuals migrating into and out of the prairie, and predation of squirrels by hawks, coyotes, foxes, cats, weasels, etc.† The first adult male was captured on 9 April and the first adult female was captured on 23 April.† Adult males emerge from hibernation before females in order to establish territories and to build up sufficient body mass to defend those territories from rival males.† Bite wounds on the rumps of males, resulting from territorial conflicts, were commonly observed.† The brome grass areas in the southern portion of the property, adjacent to the silos and along the driveway were most commonly used in the beginning of the summer because they provided the cover that this species prefers.† Use of the prairie restorations, including the north prairie that was burned in the spring, increased throughout the summer as the vegetation in these areas grew.† Most of the burrows were placed in the better-drained portions of the property.† There also seemed to be a loose association with burrow placement and trees.† On two separate occasions I observed a ground squirrel climb into a mulberry tree (to a height of about 6 feet) along the driveway after I release it from a trap.† Iíve read other accounts of this climbing behavior and a tendency to place burrows near trees and shrubs, or along marginal prairie edge.† Home ranges of adult males were generally larger than those of adult females.† There was a large overlap in the ranges of both sexes suggesting, at least in part, a colonial lifestyle.
Juveniles first appeared in the Barnhart Prairie in the middle of July.† A total of 14 juvenile Franklinís ground squirrels were radio-collared, including one that was albino.† Movement of juveniles was limited to the area immediately around their natal burrow (the burrow in which they were born) for the first week after weaning, but their areas of activity rapidly increased within a few weeks.† Eventually juveniles from multiple litters were spending the nights in communal burrows and individuals were routinely moving 200-400 meters away from these ďhomeĒ burrows before returning to spend the night.† Longer exploratory movements preceded actual dispersal (defined as a permanent shift in an animals home range).† Juveniles were commonly found in the newly planted prairie on the west side of the property (which contained primarily old field weeds) and some seemed to actually travel back and forth along it, to the west and north, to the edge of Old Church Road.† All of the fourteen collared animals moved away from their natal burrows and all but one moved out of the prairie at some point during dispersal.† Four squirrels ended up returning to the prairie and settling into hibernation burrows there.† I was able to follow two males off site until they established new territories.† One of these (House Male) moved a little over a kilometer south to the prairie patch on the extreme south end of the Barnhart property, adjacent to County Road 1100 N.† Trapping in this area revealed that other adult Franklinís ground squirrels were present.† The other male (Driveway Male) traveled approximately 5 km, to the northwest and then to the northeast, and settled in a grassy patch on the corner of Windsor Rd. and Philo Rd. in another Franklinís ground squirrel colony.† The remainder of the collared squirrels were lost at some point during their dispersal due to transmitter failure, long distance dispersal, or predation.
Below are maps of the movements of the six individuals that I was able to follow until hibernation.† Each point represents a single location of an animal.† These points were recorded either in the morning before the animal emerged from its burrow, mid-morning, or mid-afternoon.† Natal burrows and communal burrows are indicated.† The dashed arrows represent general direction of movement and not exact paths.† Most of these maps represent activity that took place during a 1-2 month span.
North Female first appeared in the north prairie circle and used two communal burrows with her littermates and other juveniles.† She proceeded to move westward during the days through the new prairie plantings but returned to Communal Burrow 2 for the nights, but eventually settled in a burrow on the edge of Old Church Rd.
Driveway Female started in a burrow along the driveway and moved to a communal burrow in the bean field adjacent to the north prairie circle.† She explored the area around the west prairie circle before settling in a burrow on the west side of the north prairie.
South Female was born in a burrow on the southwest corner of the prairie and spent time in the new prairie planting in the southwest until she moved out to the roadside on Race St. This movement took place in about 4-5 hours.† She spent the night in a burrow on Race St. and moved back to the prairie the next day.
South Male started in a burrow in the southwest and was possibly a littermate of South Female.† He eventually moved off of the property to the southeast and was located on the edge of a bean field on the corner of 1100N and 1500E.† He spent the night somewhere in this area and was located the next day north on 1500E and then moved back to the prairie later that day.† He spent a few days in the north prairie before moving to a hibernation burrow in the southeast corner.
House Male was born in a burrow next to the silos and spent most of his time in the yard prior to mowing and in the north prairie.† He began to make longer trips to the northwest into the new prairie plantings before dispersing to the extreme south prairie and roadside of 1100N.
Driveway Male spent most of his time initially in the grassy strip along the driveway and in the north prairie circle.† Longer movements to the west along the new prairie planting preceded dispersal.† He moved northwest to the corner of Race St. and Curtis Rd. where he spent the night in a roadside burrow and then moved northeast the next day to a grassy patch on the corner of Philo Rd. and Windsor Rd.