This bluetit on the outside ...
It's not just Box3 that has visitors. We seem to have a couple of birds interested in Box1 too.
... doesn't appear to be welcomed by the bluetit inside.
These pictures of bluetits in flight never cease to amaze me. Their feathers appear to be so delicate that it seems that they must easily get damaged - and yet they manage to last the whole year!
This one is not as good - in fact it's difficult to make out what is going on here.