I quickly learned this morning that Tree Swallows may be small but will bravely and fiercely defend their home. They only tolerate a person coming just so close before they take to swooping and diving at the trespasser.
With the direct approach seeming a bit unsafe, I opted to take cover on the ground next to a bush near one of the nesting boxes. After a few minutes of sitting quietly, the bird returned and paid no attention to me snapping away below.
This Swallow was evidently a male for it warned off others of it's kind attempting to check out the box.