There are no known records of timber rattlesnakes occurring in McHenry County. This species of snake is listed as Threatened in Illinois and is found mainly in the southernmost counties of Illinois. Fox snakes are common in your area and are commonly confused with rattlesnakes. They will rattle their tails to warn off potential predators. However, they do not actually have rattles on their tails and they are not venomous. If the snake does have rattles, it would be best to hire a nuisance wildlife control operator to remove the snake for you. If you can get a picture of the snake I can help you identify it. The Illinois Natural History Survey has a great website about snakes with photos and distribution maps. It can be found at:
http://www.inhs.illinois.edu/animals_plants/herps/ilspecies.html
As long as the kids are not bothering the snake it should not pose any threat to them. Snakes prefer to stay away from people if they can.
