Last summer, a pair of Tree swallows made a nest in one of the purple martin gourds. Usually they nest within 100 feet of water and bathe by skimming across the water. My yard isn’t anywhere near water, so they are nesting in an atypical location.
This year, they were back at the martin gourd along until they noticed a pair of Eastern bluebirds checking out a nearby box. They kept swooping down on the bluebirds and eventually knocked the female off of the top of the box and had a rumble on the ground. The next day, the swallows had taken up residence in the bluebird box. The female did most of the nest building, using dried grass and lined it with feathers. I checked on it about a week later and she had laid six eggs.
The eggs hatched this week, so the parents have been busy swooping and doing aerobatics catching insects and speeding back to the box. It’s funny to watch them. One will fly into the box, feed and sit with their head sticking out of the hole until a few seconds before the other flies in. Some how they seem to be communicating and will guard the nest until the other parent brings food