There are a couple of tree swallows nesting in a nest box I put up about 6 years ago. We painted nest boxes as a project one summer, my Mom, my niece and nephew, and I. I think theirs went the way of kid projects, and my Mom left hers here, but it broke. So this is what survives. (I know now that you're not supposed to paint them. Oops.)
The first couple of years, a wren filled it with stuff, but didn't nest there. And then it seemed to be ignored. But now, there are a couple of tree swallows hanging out there. There's no real place to perch right there, except on top, so fairly often, there's one perched on top.
I've been meaning to take pictures, and today was the day (and I also took some of the strawberries, which I'll post soon). I took out my camera with the telephoto and the tripod, and started a good 20 feet away, hoping not to bother the bird. And the bird seemed to notice me, but not pay a huge amount of attention. So I moved closer. And then closer. And then, even closer. Finally, I went around to the other side. And moved closer.
And this was one cooperative bird. At the end, he looked a little nervous, hunkered like he was about to take off, so I didn't move closer. Maybe if I go out there fairly often, they'll get used to me?
Here he is, hunkering a bit.