The Feather Games
I read somewhere that Swallows will play a game where a feather is blown high up into the air and the bird will retrieve it. I tried it and it worked and we played the game for days.....until young ones hatched out and then he ran me off lol. The nest box was on the front porch and we had to use the back door, true story!!!
from Bird Watcher's General Store
Although Tree Swallows like their boxes to be simple on the outside, they like it fancier on the inside. In addition to the typical nesting material, they have a little secret. Tree Swallows have a feather fetish. They love to line their nests with feathers, especially white feathers, and no one is really sure why. Some researchers have suggested that it has to do with camouflage or insulation. If Freud were a birder he may have proposed that these little birds harbor a latent desire to be swans. (Sigmund sure had some wacky ideas.)
Tree Swallows don't mind people.
Tree Swallow facts from Sialis
Males develop a brood patch and may help incubate eggs.
They eat, drink and bath on the fly (their legs are not very strong.) They may be seen picking up grit on the ground (and of nesting material of course.)
They will "play" with feathers used to line the nest (dropping and recatching them in flight.)
Tree Swallow (Tachycineta bicolor)
update: The Swallows are trying to take the Bluebird's nest box away from them but I think the Bluebirds are holding their own. I provided them a nesting box but they weren't interested.