I'm not sure if a thread like this exists, I have seen the other threads but I believe they are worldwide rather than in the UK, so my apologies if I reposted a thread that already existed. Anyways, what is the rarest bird that you have seen in the UK? Mine would probably be a Chough which was sited by me in Wales. Another close competitor was a few gannets in the same location as the chough. It was certainly a really good day. I'll have to find some images later as well.