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DUCKS, GEESE, AND SWANS. 207 
March, and the migration continues through the 
whole of April into May, the bird thus being one of 
the last Ducks to retire north in spring. Although 
by no means unfrequently met with on inland waters 
during migration and in winter, the Scaup Duck is, 
for the most part, a dweller on the sea, resorting, by 
preference, to bays, estuaries, and the mouths of 
large rivers, especially where a considerable amount 
of mud is left bare at low water. It is gregarious 
at this season, often congregating into large flocks, 
and not unfrequently associates with other Sea 
Ducks, notably with Wigeon and Pintail. It isa 
most expert and ready diver, spends most of its 
time upon the water, and appears always to prefer 
to dive, rather than to fly, in avoiding pursuit. If 
compelled to take wing, it rises with much splashing: 
but, when once fairly in the air, is capable of rapid 
flight, the quickly-beating pinions making a whistling 
or rustling sound. The food of the Scaup Duck 
consists largely of molluscs, but crustaceans and 
marine plants are also eaten by this species. When 
thus diving for food, the bird often remains below 
for a minute at atime. It feeds much at night, and 
"passes pretty regularly from its usual haunts by day 
to its feeding-places. The note of this Duck is a 
most harsh and discordant scawp, but during flight 
or courtship a hoarse and grating kurr is uttered. 
The Scaup Duck arrives at its Arctic breeding- 
grounds with the break-up of the ice. The bird 
may probably pair for life, as the sexes keep close 
