It been another good year for White-Wingers at Shawell and I was thinking when are the best times for finding one. Below is a graph showing the finding month of all the Glaucous and Iceland Gulls sighted at Shawell so far. I thought that Iceland Gulls generally arrive later than Glaucs, but as you can see either can turn up at anytime during the winter months. There is, however, a peak in January for Glaucous Gulls and March for Iceland.
Judging by the numbers of Iceland Gulls seen so far I wouldn't bet against breaking the latest date for the site. The latest date is April 15th 2017.