We have a tall playset -- tall enough that T. doesn't tend to go up to the very top, stopping at the slide level. Which is good, because some birds built a nest (and dropped nesting materials all over the place while doing so, which I am prepared to tolerate in the spirit in which I let T. leave toys all over the house) in the top level. There's a fabric roof/cover at the top of the tower, so this is a pretty great spot. R. noticed the traffic in and house of the tower, and investigated, finding the nest and the (IIRC) 4 eggs in it. He's been keeping an eye on it (and we've been making sure T. doesn't disturb it) and yesterday he checked again when I asked if that was a bird in the nest. He wanted to make sure we didn't have an abandoned failed clutch of soon-to-be-rotten eggs.
Well, we have no adorable pictures, because _I'm_ not going to interfere with this process, but we apparently have 4 extremely cute baby birds. I'll ask R. later what kind they are; I haven't gone up to look myself.