356 FLAMINGOES, DUCKS, AND SCREAMERS. 
it is dusky greyish brown. The scoters, of which there are five species, although 
confined to the Northern Hemisphere, are far less exclusively Arctic birds than the 
eiders. The common scoter (Z. nigra), which inhabits a large portion of Europe 
and Northern Asia, is characterised by the entire plumage of the male being black. 
In Japan and North America it is replaced by the American scoter (ZH. americana), 
in which the whole of the protuberance at the base of the beak is orange-yellow, 
instead of mainly blackish blue. The velvet scoter (4. fusca), which is also a 
winter visitor to the British Islands, although far less common than the preceding, 
differs in that the male has a small white patch behind the eye, and a white 
speculum on the wing. Widely spread along the more northern coasts of Europe. 
and Asia, this scoter is represented by a variety in North America. As another 
very well-marked member of the genus, mention may be made of the North 
American surf-scoter (Hf. perspicillata), of which stragglers occasionally reach 
Britain. The male may be recognised in its breeding-plumage by the presence of 
one broad patch of white on the forehead and another on the nape of the neck. 
All the scoters are regular migrants, and marine and gregarious in their habits; 
the common species assembling in such countless numbers on the British coasts in 
winter, as on some occasions to cause the water to appear literally black. Scoters 
generally arrive from their summer-quarters in September and October, and return 
in the following April or May. During the breeding-season the flocks of adults 
break up into pairs; although this is not the case with the immature birds, which 
do not breed during their first spring, but remain congregated throughout the 
summer. Moreover, in the case of both the common and the surf-scoter, flocks of 
these immature birds frequent the British Islands during summer, instead of going 
northwards. All the scoters are late breeders; the nidification of the common 
species not beginning in Iceland till the middle of June, while in Arctic Russia it 
is deferred for a fortnight or so later. Islands in the rivers and lakes of the 
Arctic tundras, where the ground is covered with dwarf birch and willow, form the 
favourite breeding-grounds of the scoters; and the eggs, which are usually from 
five to nine in number, are deposited in a mere hole in the ground; those of the 
common species being greyish buff in colour, with a dull exterior. Although 
rather awkward walkers, all the scoters fly with rapidity, and are fully equal to 
their allies in swimming and diving. Their food in winter consists of various 
small aquatic invertebrates, and in summer of water-plants; their flesh being 
almost uneatable. Remains of extinct scoters, which have been referred to the 
genus Huligula, used in a wide sense, occur in the Lower Miocene strata of France, 
which have also yielded others belonging to typical ducks and described as 
Anas. 
The Stiff-Tailed The genus Hrismatura comprises species known as stiff-tailed 
Ducks. ducks, all of which are lacustrine rather than marine in their habits, 
and many of which are characteristic of the Southern Hemisphere. While agreeing 
with the preceding genera in their broad and depressed beaks, these ducks are dis- 
tinguished by the feathers of the tail being narrow and very rigid, with the inferior 
surface grooved. Moreover, the tail-coverts are so short as searcely to overlap the 
base of the tail, which is rather long and graduated, and may contain as many as 
twenty-four feathers. All are said to be expert divers, and in flight and habits some 
