Home range, habitat use, and behavior of the eastern diamondback rattlesnake (Crotalus adamanteus) on the Ordway Preserve

Abstract

The eastern diamondback rattlesnake (Crotalus adamanteus Beauvois) was studied by radio-telemetry from 3 September 1985 to 21 February 1989 at the Katharine Ordway Preserve/Carl S. Swisher Memorial Sanctuary, Putnam County, Florida. Five male and three female snakes were monitored for durations ranging from 33 days (11 observations) for a small female to 864 days (245 observations) for an adult male. Intervals between observations averaged 3.3 days. A total of 743 observations was used to determine home range, habitat use, movements and other behaviors for this species. Diamondback home ranges were analyzed using the McPAAI computer program (Smithsonian Institution). Females (n=2) maintained smaller home ranges (mean = 46.5 ha) than males (n=4, mean = 84.3 ha). The ranges of both males and females overlapped, indicating that this species is not territorial. Diamondback activity patterns suggest that they occupy stable home ranges that remain similar from year to year. Although rattlesnakes were recorded in all habitats available to them, the Swamp Forest/Mesic Hammocks and Xeric Hammocks were favored. They also utilized Wet Prairies during droughts. Eastern diamondbacks were almost entirely terrestrial, rarely climbing into trees (n=1) and infrequently going underground (n=35) during their activity season. During winter (Dec-Jan-Feb) rattlesnake movements decreased, but they remained on the surface 55.4% of the time. Burrows of armadillo (Dasypus novemcinctus, n=57) and gopher tortoise (Gopherus polyphemus, n=12), as well as root channels beneath stands of palmettos, were used as winter refugia. Mean monthly distances traveled increased during fall (Sep·Oct-Nov), when snake movements averaged over 20 m per day. At this time males made longer moves, probably searching f6r breeding females, whereas females made shorter movements. Movements were always made during daylight hours. The hunting strategy of C. adamanteus consisted of a sit-and-wait foraging behavior, with the main posture a tight coil from which it might ambush prey. Snakes spent anywhere from one day to almost a weekcoiled in the same hunting location. Necropsies of 14 rattlesnakes (from north-central Florida) that contained identifiable prey remains indicate that the cotton rat (Sigmodon hispidus, n=8) and the rabbit (probably Sylvilagus floridanus, n=5) are the numerically dominant prey; one sample included a white-footed mouse (probably Peromyscus gosopinus); other evidence identified the wood rat (Neotoma floridana) as prey for the eastern diamondback.