There is not a state law that prohibits feeding wildlife such as birds, squirrels, chipmunks, etc. (It is illegal to feed deer in Illinois). But, there are some communities with ordinances against feeding wildlife. You'll need to call your local officials to see if there is anything on the books in your town. Some people really like feeding wildlife because it gives them a sense of connection with nature. If this is a situation where you think there can be a compromise, try talking to your neighbor and see if he'd be willing to go out watch the wildlife without feeding them on a regular basis. Maybe he'd be willing to feed the animals once a week rather than daily. Wildlife do not need supplemental feeding from people. In fact, it often draws in more animals to an area than the habitat can support. This can cause spread of disease and increases the animals' stress levels. If the numbers are really getting out of control, rat traps will work on chipmunks. Squirrels can be trapped by nuisance wildlife control operators. Hopefully the situation doesn't have to reach that point.
