BOB is an American Kestrel, Falco sparverius, or Sparrow Hawk, though these birds more commonly hunt for small mammals or insects.They are regularly seen hunting along parkways and in suburban fields. As with all birds of prey, the female is larger than the male and can be distinguished by her rusty red wings, where males like Bob have wings that are blue grey.

Bob has an injury to his wing that makes him non-releasable, as he is not fully flighted. Kestrels have two hunting methods- they may wait on a treetop, pole or telephone wire until prey is sighted, then take off in a dive or glide to catch it. Or they may fly over a field and hover on fast beating wings (kite) before dropping to catch the prey.

Bob is the smallest member of the Falcon family, and ha the facial markings, or mustaches, characteristic of falcons.