I agree, the SIN is a great resource, but is rather specific to the Ontario S.c.c., which is a unique cluster of populations. From people I've talked to, the situation is somewhat grim in Illinois. Jennifer Szymanski at the USFWS coordinated the writing of a status assesment of the eastern massasauga, and may be a good contact. Also, the USFWS published "The Eastern Massasauga Rattlesnake: A Handbook for Land Managers" which discusses the general biology, population status, and managment practices. It may be a good place to look, and use in conjunction with the SIN.