We've had swift boxes on our house for about 9 years now. Last year, for the first time one of the boxes was occupied, but I don't think they bred. This year I'm hoping that after all these years we really do have a breeding pair. I've been watching regular activity these last few days - indicating that probably there's a bird incubating eggs with regular visits from a mate who's feeding her.
I've taken quite a few photos, but they're all rubbish.
Wish me luck...