KEY TO DUCKS, GEESE AND SWANS OF NORTH AMERICA. 35 



Section 3. Head, brownish or grayish, sometimes marked 



with white. 



Forehead and feathers at base of bill, white ; nail of bill (unguis), whitish ; 



bill, yellowish; breast, grayish, more or less marked or spotted with black. 



American White Fronted Goose. 



Anser alhifrons gambeli {adult) . 

 See page 83. 



No white on forehead or base of bill; bill, yellowish; nail of bill (unguis), 



dusky ; rump, slaty brown ; wing coverts, edged with white. 



American White Fronted Qoose. 



Anser alhifrons gambeli (immature) . 

 See page 83. 



Qeneral plumage, grayish ; rump, white ; smaller than C. h. nivalis; bill, over 

 1.90; tarsus, over 2.80; middle toe, over 2.10 (immature). Chiefly Pacific coast 

 to Mississippi Valley, rare on Atlantic coast. 



Lesser Snow Qoose. 



Chen hyperborea (immature). 

 See page 80. 



Qeneral plumage, grayish ; rump, white ; larger than either nivatis or rossii. 

 Eastern North America, south in winter to Florida and Cuba. 



Greater Snow Qoose. 



Ghen hyperborea nivatis (immature). 

 See page 81. 



General plumage, grayish; rump, white; bill, 1.50 to 1.75; tarsus, 2.25 to 3; 

 middle toe, 1.80 to 2.05. Pacific coast, east to Montana, not found on Atlanitc 

 coast. 



Ross's Snow Qoose, 



Chen Sossii (immature) . 

 See page 82. 



Head, brownish gray ; chin, white ; rump, gray ; unguis (nail or bill), yellow ; 

 wing coverts, grayish, showing very little white on the edge of the feathers. 



Blue Goose. 



Chen ccerulescens (immature) ■ 

 See page 81. 



Head, plumbeous, speckled with white ; general plumage, plumbeous ash; the 

 feathers barred near tip with black and white; terminal half of tail, white 



(immature). Alaska, casual on Pacific coast to California; does not occur in 

 Eastern North America. 



Emperor Qoose. 



Philacte canagica. 

 See page 87. 



