THE SPATIAL ECOLOGY OF THE EASTERN MASSASAUGA (SISTRURUS C-CATENATUS) IN NORTHERN MICHIGAN

We investigated the spatial ecology of the eastern massasauga (Sistrurus c. catenatus) at a study site unique in that it was near the northern extent of the species' geographic range and had a sandy substrate and extensive mixed coniferous forest. Forty-six individuals were radiotracked for at least one complete season between 2002 and 2004 or 2006 and 2007. Males had larger home ranges and core areas, range lengths, and movement rates than nongravid females, which in turn had larger movement parameters than those of gravid females. Movement rates and distances were not constant throughout the activity season, with males making greater movements as the activity season progressed and gravid females making the longest movements immediately following parturition. Total area used during the activity season was intermediate relative to that used by massasaugas at other sites, with minimum convex polygons around outermost observations during the active season averaging 16.7 ha. Movement indices at our site were much larger than reported indices from study sites in the central or southern portions of the massasauga's geographic range and mole similar to those from Ontario and New York. The trend for increased movements at northern latitudes may have implications for managers attempting to provide sufficient habitat for viable populations and minimize interactions between snakes and roads or other anthropogenic disturbances.