Hi there,
We've recently started getting some good footage of the birds at our bird feeder and saw this guy earlier today. Is this sort of deformity common?
Someone one has beaten me to it with the BTO link.
The can often thrive quite well, learning to adapt to their situation.
I had a coal tit with a crossed mandible (beak) and it seemed to go on forever, even having a brood. The latest is there are some small cola tits with crossed mandibles, at a wild guess, possibly one of the parents was the one I first spotted last year.
If you want to see the progress of the original coal tit, you can view that thread here:
https://community.rspb.org.uk/wildlife/f/wildlife-questions/207056/coal-tit-with-crossed-over-beak