INTRODUCTION 11 



and in numbers of individuals. In a general way it may be said that those parts of 

 the temperate and subarctic regions embracing huge tracts of poorly drained plains 

 and steppes are the true home of the duck tribe. The great inland breeding grounds 

 of western North America support some twenty-three species, whereas the rocky 

 barrens that lie east of Hudson Bay support regularly only three or four. In the same 

 way the huge wild-fowl reservoir extending from eastern Germany through Finland, 

 Russia, and Siberia supports great hordes of water-fowl that winter as far south as 

 the White Nile, Abyssinia, and East Africa on the west, and northern India and 

 China on the east. The North American ducks may be said to winter from the 

 northern States as far south as the Great Central Valley of Mexico, but the bulk of 

 them remain along the South Atlantic and Gulf Coasts and the central valleys of 

 California. 



The tropical rain forests, all over the world, are poor in the number of duck spe- 

 cies. The Congo and the Amazon basins are noteworthy in that respect, for they 

 support no true surface-feeding ducks and only a few species belonging to gooselike 

 genera that have mostly arboreal habits. Polynesia and Melanesia are likewise re- 

 markable for the extreme poverty of their duck fauna; for throughout all the Pacific 

 Islands we have only one true, wide-ranging species, the Australian Black Duck, 

 while a few straggling migrants are attracted from Alaska and the Chinese mainland. 

 On one or two oceanic islands are found isolated species, such as the Hawaiian Duck, 

 the Laysan Teal, the Coues' Gadwall, and the Guam Island Duck. 



In India and Burma are found a goodly variety of ducks, part migrants and part 

 isolated and local species, such as the curious Pink-headed Duck and the little-known 

 White-winged Wood Duck. 



Coming now to the southern continents, we find the ducks very richly represented 

 in southern South America, south of the rain forests, as well as in South Africa, 

 Australia, and New Zealand. In all this Southern Hemisphere, of less rigorous win- 

 ters, but with well-defined wet and dry seasons, migrations are not so marked, nor so 

 clearly understood as in the north; the breeding season extends over a longer period, 

 and all species tend to become dependent on local water conditions and therefore 

 more erratic in their movements. They may even breed over their whole range, a 

 condition very seldom seen among the northern ducks. 



Southern South America supports twenty-eight species of ducks, and is note- 

 worthy for its richness in teal. Those species which extend into the lakes of the high 

 Andean plateau have tended to become local, to increase in size, and to form new 

 but not very different species. In South America also we find the wholly unique 

 semi-flightless Steamer Duck, the largest of all the ducks, while high up amid the 

 snows on the western slopes of the Andean range, the very interesting little Mergan- 

 ser-like Torrent Ducks, perhaps related to the grebes, which in scattered pairs occupy 

 the streams, and are to this day little known. 



