LIST AND DESCRIPTION 57 
166. SurF ScoTeR (Oidemia perspicillata.) 
A large Duck. Rare in migration. Male: black, with 
crown and nape white. Female: above black, breast dusky; 
belly lighter; white patch at base of bill. In both sexes black 
feathers extend forward on top of bill. A female in the Museum 
was taken on Lake Madison by Mr. J. C. Green, of Sioux Falls, 
in 1914. 
167. Ruppy Duck (Erismatura jamaicensis.) ‘“BUTTERBALL.” 
Breeds quite commonly in the State, building floating 
nests in high rushes. A very small Duck, but Mr. F. A. Patton 
says that “the eggs are of the same size as those of the larger 
Ducks.” Male: crown black; cheeks white; back and neck red- 
dish brown. Female: head dusky; back grayish brown; belly 
white. Tail feathers narrow and stiff in both sexes. 
SUB FAMILY ANSERINA. GEHESE 
Geese are intermediate between Ducks and Swans in size 
and in length of neck. They are the largest of our aquatic game 
birds and are more terrestrial in their habits than Ducks. They 
feed almost entirely on vegetable foods—stubble or cornfields, 
winter grainfields, or tender grass shoots in the water. There 
is little difference in plumage between sexes; they lack the highly 
contrasted colors of Ducks. Eight species or varieties, usually 
called “Wild Geese,” are mostly migrants in South Dakota. 
169. Snow Goose (Chen hyperboreus hyperboreus.) 
Length from tip of bill to end of tail about twenty-six 
inches; all white except the longest wing feathers or primaries, 
which are black. A western species that breeds in Alaska and is 
common in South Dakota in migration. 
169a. GREATER SNow Goose (Chen hyperboreus nivalis.) 
Rare; seen only in migration. An eastern variety that 
breeds in the Arctic regions. Similar to 169 but larger, length 
up to thirty-eight inches. 
169. 1. BLur Goose (Chen caerulescens.) 
Rare in migration. About the size of the Snow Goose. 
Head and neck white ; body bluish gray ; rump lighter. 
