Always Watching

The Tree Swallow is an awesome little jet fighter,and the male will defend a relatively large territory around the nest box. I have seen this little spit fire dive bomb cats and is said to be one of the most aggressive swallows. Here on the homestead they eagerly use artificial nest boxes, and they are often seen carrying goose or duck feathers back to their nest.

You will always know if a pair of Tree Swallows moved into your nest box. They always pop their little heads out , and watch your every move.
Maybe just being curious, or maybe they are planning their next sortie, and you are the target.