Habitat Use by Three Species of Snakes at the Middle Fork Fish and Wildlife Area, Illinois

Abstract

We used radiotelemetry to determine habitat use by 11 black rat snakes (Elaphe obsoleta obsoleta), five fox snakes (Elaphe vulpina vulpina) and four blue racers (Coluber constrictor foxii) at the Middle Fork Fish and Wildlife Area in east-central Illinois in 1997 and 1998. Black rat snakes selected forested habitats, whereas fox snakes and blue racers selected old fields and prairie restorations. No consistent association with forest- field edges was noted for any species. Fox snakes and blue racers were primarily terrestrial, whereas black rat snakes used all categories of vertical space but were primarily arboreal. Snakes were tracked to three hibernation sites, including an abandoned railroad trestle and two abandoned trash and construction-material dumps. These data provide the first comparative, quantitative descriptions of habitat use for these species in sympatry, and one of the few descriptions of hibemacula in a region dominated by row-crop agriculture. Due to their secretive behavior, snakes are difficult to study in the field and many impor- tant features of their ecology and natural history are not well known (Seigel et al., 1987; Seigel and Collins, 1993). Snakes also are frequently considered vermin and often indiscriminately killed by humans (Dodd, 1987; Greene, 1997). Because many species of snakes are declining in numbers (Dodd, 1987; Greene, 1997), it is im- portant to identify and protect critical habitats and landscape features relevant to their conser- vation. In temperate regions, sites used as hi- bemacula may be particularly important to the persistence of populations of many species of snakes (e.g., Prior and Weatherhead, 1996; Bur- brink et al., 1998). However, little information exists about habitat selection and sites used as hiberacula by snakes in agricultural regions of the midwestern United States.