I’ve just seen a great tit in my garden with a large tumor on its side and eye and it looks like pictures I’ve seen about avarian pox. What do I need to do and how much of a threat is this to the rest of the birds in the garden?

Hi Claire,   Avian Pox is extremely contagious viral disease amongst birds that come into direct contact with the infected bird or surfaces the infected bird has used where the virus can linger, hence the best course of action as in the link that Mr B provided is to keep feeding areas cleaned daily using their advice using mild disinfectant and air drying feeders and tables, bird baths,     If you see more than two birds with Avian Pox then it is best to withdraw all feeders, dishes, etc., for three weeks or so in order to give time for the garden birds to disperse so there is less chance of the pox transferring from one sick bird to a healthy bird.     The good news is that even birds with severe Avian Pox can fully recover, it is not necessarily a death sentence for them.   So keep your eye on things and hopefully you won't see additional cases where you would have to withdraw feeding them for a while.    

HERE is another article you may wish to read.   It dates back to 2011 and I think Avian Pox has certainly spread further north as we've seen several cases here in Cheshire.