There are many species of hawks, but they are not always easy to see. You have to watch for them, or listen for their calls (a high pitched screech.... varies with each species). If you are lucky, you may see one perched in a tree, or on a telephone line. They can often be spotted circling overhead. You can often tell that a hawk is in the area by listening to the complaining chirps from songbirds such as Blue-Jays.
Red Shouldered Hawk (Buteo lineatus)
I have seen the smaller Red-Shouldered Hawk catch chipmunks, and the larger hawks catch grey squirrels. They also feed on mice, moles, and snakes.