Several species of hawks eat songbirds and rodents as their natural food. This is part of nature's predator-prey relationship that is in balance.
In fact seeing a hawk at the feeder is a good sign. Unlike other birds, hawks reproduce very slowly and we are only now seeing many raptor populations recover from the massive deaths that occurred in the early 1900s from hunting and the 1960s from DDT. And other human-caused problems such as loss of nesting habitat, highway vehicles and electrical wires continue to impact the population of certain raptor species in many areas.
Ultimately, the only thing you can do when a hawk comes to dinner is wait it out. Most hawks that settle in at feeders do so for two or three weeks and then they are off again to different territory.
What is the smallest hawk in North America? http://bit.ly/xWaTsR
Red-tailed Hawk Fun Facts http://bit.ly/AaK61o
Coopers's Hawk http://bit.ly/y5cNMz
Northern Goshawk http://bit.ly/xcEcW7
Most common winter hawks in Michigan http://goo.gl/2E68L