King Eiders come out of eclipse plumage much later than Common Eiders. I remember, when there were up to 3 regularly on the East Sutherland coast in the 1970’s, that they did not attain full plumage before late December or even January. Full breeding plumage is even later. In May last year the drake over on the Ythan in Aberdeen-shire was spectacular. The shields on either side of the bill were twice the size of a winter bird. I had never realised before that the comb was indeed split either side of the bill. Certainly well worth the effort of a trip if it makes a return next spring.