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. Ruddy 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 ANSERINE. GEESE 



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 hyperbnreus 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. Blue Goose (Chen caerulescens.) 



Rare in migration. About the size of the Snow Goose. 

 Head and neck white ; body bluish gray ; rump lighter. 



