Franklin's Ground Squirrel (Spermophilus franklinii) in Illinois: A Declining Prairie Mammal?

Abstract

Franklin's ground squirrel (Spermophilus franklinii) appears to be becoming increasingly uncommon in the eastern portion of its range, but current data on its status in Illinois are lacking. We conducted a mail survey of 166 wildlife professionals from throughout the historical range of the species in Illinois to obtain information pertaining to extant and extirpated populations and local population trends. Locations of potential populations were compared with 106 known historical points of occurrence. Twenty-six sites were chosen for livetrapping surveys to confirm the presence or absence of the species. We considered it likely that Franklin's ground squirrels might persist in these sites due to information provided in the mail survey and/or known historical occupancy. Franklin's ground squirrels inhabited only 3 of the 26 trapping sites; however, we located two other areas of probable occurrence in addition to the locations that we surveyed. While it is clear that Franklin's ground squirrel has declined in Illinois, the magnitude of this decline remains unknown due to the secretive behavior of the species and a lack of knowledge about its ecology. The methods described in this paper are an efficient means of collecting initial information concerning the status of a species that is difficult to observe or about which little is known.