The tree swallow has been joined by a second, probably a female by the way they are tolerating each other.
Earlier, I thought it was a second male, but it turns out that mature female tree swallows are very similar to males.
(Immature females are brown-backed, instead of irridescent blue-green)
When I told Geoff this, he said, "Oh, good. I thought we had gay tree swallows. Not that there's anything wrong with that...it's perfectly fine..but now they can make babies..." and there he trailed off.
LOL...my eminently PC husband.