Lesser Scaup - Distribution and Migration

Distribution and Migration

Their breeding habitat is inland lakes and marsh ponds in tundra from Alaska through western Canada to western Montana; few breed east of James Bay and the Great Lakes. Notable breeding concentrations, with more than half a million birds at the height of the season, can be found in Alaska, in the woodlands of the McKenzie River valley and on the Old Crow Flats. These birds migrate south (mostly via the Central and Mississippi Flyways) when the young are fledged and return in early spring, usually arriving on the breeding ground in May. Lesser Scaup typically travel in flocks of 25-50 birds and winter mainly on lakes, rivers and sheltered coastal lagoons and bays between the US-Canadian border and northern Colombia, including Central America, the West Indies and Bermuda. Wintering Lesser Scaup are typically found in freshwater or slightly brackish habitat and unlike Greater Scaup rarely are seen offshore when unfrozen freshwater habitat is available. They may even spend the winter on lakes in parks, as long as they are not harassed, and will occur even on smallish Caribbean islands such as Grand Cayman. Thousands winter each year on the Topolobampo lagoons in Mexico, and even in the southernmost major wintering location – Ciénaga Grande de Santa Marta in Colombia – hundreds of birds can be seen. In Central America, flocks are present from July on, but only really numerous after September. They move north again in April and May. In the extreme southeast and southwest of the breeding range – the Rocky Mountains region of the northwestern USA and the southern Great Lakes – Lesser Scaup are present all-year; it is not clear whether the breeding birds are replaced by migrants from the far north in winter, or whether the local populations do not migrate, or whether both local and migrant birds are found there in winter.

They are rarely – but apparently increasingly often – seen as vagrants in western Europe. The first documented British record was a first-winter male at 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).