Sharp-shinned Hawk

When I first saw it, it was perched in our Silver Maple and the rest of the feeder area was totally empty of other birds. By its size and the narrow white edging on its tail feathers, as well as its square tail, rather than the slight rounded curve of a Cooper's, we identified it as a juvenile Sharp-shinned Hawk. The second time it arrived; it swooped in fast, and just as fast a flight of little birds erupted flying in the opposite direction. It didn't give chase but it did pounce on something on the ground nearby; although I wonder if it was just practicing pouncing for there was no sign of any prey there.