shut in or shut out

yesterday there was a blue tit (or 2 perhaps) going in and out of this house. this morning i woke up to find all that stuff half hanging out and half blocking the entrance - i can only assume the blue tits know what they are doing and that they havent either locked themselves out or in!
but there was no sign of a blue tit about the house today.
loads of them in the garden and surrounding trees.
another lovely sunny day, although it clouded over by about half four. still, we went for a walk, it was good to be clambering thorugh barbed wire, muddy fields and wooded bits among hills.