Habitat Use and Movement Patterns of the Eastern Massasauga Rattlesnake in Wisconsin

Abstract

The eastern massasauga rattlesnake (Sistrurus catenatus catenatus) has been listed as endangered in Wisconsin since 1975. The current status of the massasauga in Wisconsin is uncertain. A recent statewide survey located only 9 specimens throughout the state. Little is known about its life history or habits, other than its preference for lowland habitats. Radio-telemetry was used to determine habitat use and movement patterns of monitored massasauga rattlesnakes (n=10) in Juneau Co., and Monroe Co., WI. Data were collected on the habitat types where the massasaugas were located. Proportional observed use values were compared to the expected values. A correlation coefficient indicated there was low correlation(0.402) between available habitat and use. A chi-square analysis was used to determine if there was a significant (critical value = 9.49, df=4) difference between the observed use of habitats, and the available habitat. The Z-statistic was used to determine if certain habitats were selected or avoided. Neonatal snakes (n=32) also were monitored. Proportional use of habitat was compared to adults by using the chi-square test and the z-statistic. Results showed that adult snakes (n=10) avoided upland forest habitats, and selectively used upland meadows and roadbeds(x^2 = 77.48). Male snakes (n=3), avoided upland forest (x^2=25.69). Female snakes (n=7) avoided upland and lowland forests, and selected upland meadows and roadbeds(x^2=124.92). Neonates used upland and lowland meadows more often than adults (x^2=47.72). Movement patterns suggest that the snake is a relatively sedentary species. The results suggest that behavior of massasaugas is similar to that of other high latitude Crotalid snake species. Females use upland meadows as basking sites and breed every other year; males and non-gravid females forage in more closed canopy areas. Each snake hibernates individually in the root systems of trees in lowland areas. Increased enforcement of current laws, public education and continued commitment to the protection of wetland habitats are probably crucial to maintaining the massasauga in Wisconsin.