I used to watch a Peregrine Falcon who would hunt the train tracks. He would perch in a tree over looking a spot where they buckled and unbuckled the cars which caused grains to spill out. Flocks of pidgeons would soon be on the grain and in a flash that Falcon would swoop down and nail one before it rose a foot off the ground. I always wondered how the Falcon chose which one it was going to kill because it was always a bee line at a specific bird with no indecision.