Common Eider Somateria mollissima
Present offshore throughout the year: fairly common on passage and in winter, scarce in summer. Mainly found in The Wash and rare inland. Under recorded because most of the population stays well offshore; however, numbers have recently declined.
Male Common Eiders at Gibraltar Point in January 2014 (Russ Telfer).
The UK wintering Eider population is in decline, the WeBS 25-year trend showing a 26% fall to winter 2018/19. Most birds in Lincolnshire winter on The Wash. The recent highest winter peak for The Wash was 3,721 in 2011/12, and the previous low was 226 in 2016/17; in winter 2018 there were 896. Birds can move around and are often far out to sea, utilising sandbanks at low tide. During a 10-year low tide count of Roger and Toft Sands, which are 4 km offshore from Wainfleet Flats and only accessible by boat, 350 were counted roosting on sandbanks in January 2020. Summer counts which have always been much lower than winter ones have also fallen. There was a low of only 2 in Jul 2018 but so far there has not been a month with no Eider recorded.