The BOURC just decided to adopt IOC taxonomy in future. We just lost Hudsonian Whimbrel and Mealy Redpoll. :(
Well, sod it. In the UK it may be usual to remove them from past Year Lists when they get lumped, but I think the ABA has a much better idea, and I'm going to keep my year lists according to the rules of the year they were listed in.
On a plus note, I no longer have any reason to make an expensive trip to Cornwall this half term for the Hudsonian whimbrel. And those who already have must be furious.