Have had a bird box up for four years. This year is the first year Blue Tits have taken up residence and raised a brood. By my reckoning there are four birds in the nest plus the two adults. Lately there seems to have been only one adult around, flying from dusk til dawn to feed the ever open mouths of the young. Guess they're going to fly any day soon as they're making their first looks out of the hole (see other pic). I'll miss them very much.