Lesser scaup breed and raise their young may be tied to some specific ecological conditions—such as abundance of key food items—which shifted winterwards due to global warming, without the ducks being able to adapt. In this regard, it is alternatively or additionally possible that greater scaup, which may be increasing in numbers, is putting the lesser scaup under increasingly severe competition. However, it seems that greater scaup eats larger food items on average, and the species are sympatric in part of their range and presumably have been for millennium without any problems due to competition. The experience of the past as well
Lesser scaup Chasewater, Staffordshire in 1987 but by 2006, over 60 had been recorded, with an average of 2 per year. UK records are typically in the northern parts of the country. Vagrant lesser scaup have also been recorded on the Hawaiian Islands Japan, possibly China, and—for the first time on 18 January 2000—in the Marianas, as well as in Ecuador, Surinam, Trinidad and Venezuela (in winter), and Greenland (in summer). Lesser scaup forage mainly by sifting through the bottom mud, usually after diving and swimming underwater, occasionally by dabbling without diving. They mainly eat mollusks such as mussels and clams, as