Cooper's hawks predominantly hunt:

Cooper's hawks are agile, medium-sized raptors known for their preference for bird prey, especially smaller songbirds. They are adept at flying through dense vegetation to ambush their targets. The correct answer reflects their primary hunting preference, which includes sparrows and starlings, but also extends to other small to medium-sized birds, such as cottontail rabbits and quail.

This versatility in hunting allows Cooper's hawks to adapt to various environments and food availability. While they may also hunt jackrabbits and cottontails at times, it is the combination of smaller birds and ground-dwelling prey like quail that truly characterizes their primary diet. Hence, the answer accurately captures the range of prey they predominantly hunt, situating themselves as opportunistic predators capable of taking advantage of different food sources within their habitat.