Ecology of the eastern massasauga (Sistrurus c. catenatus) in Piatt Co., Illinois
Allerton Park, located in east-central Illinois, is among the few remaining acres of natural area in this heavily agricultural region. Original land surveys describe the area as having an extensive floodplain forest along the Sangamon River and an area of upland timber and savanna south and east of the floodplain. Prairie dominated the remainder of the landscape.
It is doubtful that Robert Allerton had the welfare of a rattlesnake in mind when, in 1946, he donated his expansive central Illinois estate to the University of Illinois as a park and wildlife preserve. Yet it is here, among the park's forests, prairies, and wetlands that the eastern massasauga rattlesnake has found one of its last strongholds in Illinois.
Once found throughout most of the state, this shy rattler is now known to exist in fewer than ten locations. One of the largest populations-thought to number between 15 and 30--is found in Allerton Park.
Far from being a threat, the massasauga is an innocuous resident of old fields, savannas, floodplain forest, marshland, and bogs. They are attracted to the prairie to feast on the small rodents found there, particularly the prairie vole. From April through October you will find them hunting the rodents among the tall grasses or else sunning themselves on clumps of grass or in branches of small shrubs. Scientists suspect the snakes never venture more than a few yards from trees and shrubs so thatthey can scurry under cover if hawks and other predators appear.
Misunderstanding of the massasauga is still with us today. Many local residents still believe that Robert Allerton imported the rattlesnakes to scare away trespassers. Arousing sympathy for a creature commonly associated with danger, though, is difficult. But sympathy, or at least tolerance, is what this snake needs if it is to survive.
We are currently using radio-telemetry to track massasaugas at Allerton. We hope to learn about movement patterns and habitat use to aid in land management decisions. We also conduct spring egress searches to estimate population size. Evan Menzel (below, at left) and Jon Warner (below, at right) were the first students to work on this project. Evan was sponsored by the Undergraduate Mentoring in Environmental Biology (UMEB) program at the University of Illinois. Currently, John Griesbaum is conducting the research at Allerton.
Also involved are Fran Harty of The Nature Conservancy and Eric Smith of the Illinois Department of Natural Resources, Office of Resource Conservation.