ANSER. 115 



3.30, middle toe 2.15-2.50. Hab. Interior of North America, east of 

 Bocky Mountains, breeding on the eastern shores of Hudson's Bay ; 

 migrating south, in winter, through Mississippi Valley to the Gulf 

 coast ; occasional on Atlantic coast. 



— . C. caerulescens (Linn.). Blue Goose. 1 

 6 2 . Plumage of adult entirely white, except primaries and their coverts ; young 

 grayish white, the upper parts striped with dusky grayish. 



Adult : Uniform pure white, the head often stained with rusty ; pri 

 maries black, becoming grayish basally, their coverts, and the 

 alulae, ash-gray. Young : Head, neck, and upper parts pale grayish, 

 the feathers of the latter with whitish edges and (especially wing- 

 coverts and tertials) striped medially with darker; rump, upper 

 tail-coverts, tail, and lower parts plain white. 

 c 1 . Length about 23.00-28.00, wing 14.50-17.00 (16.36), culmen 1.95- 

 2.30 (2.15), tarsus 2.80-3.25 (3.01), middle toe 2.00-2.50 (2.34). 

 Eggs 3.13 X 2.12. Hab. Western North America, breeding in 

 Alaska; migrating south, in winter, to southern California and 

 Mississippi Yalley ; northeastern Asia. 



169. C. hyperborea (Pall.). lesser Snow Goose. 

 &. Length about 30.00-38.00, wing 17.35-17.50 (17.42), culmen 2.55- 

 2.70 (2.63), tarsus 3.15-3.50 (3.28), middle toe 2.60-2.80 (2.70). 

 Hab. Eastern North America ; breeding grounds unknown, but 

 probably arctic regions east of Mackenzie Eiver ; "United States 

 (Mississippi Valley to Atlantic coast) only during migrations 

 and in winter. 

 169a. C. hyperborea nivalis (Forst.). Greater Snow Goose. 

 a 2 . Bill comparatively weak, the commissure not gaping, and not enclosing a dis- 

 tinct blackish space ; feathering at base of upper mandible, along each side, 

 forming a nearly straight, oblique line ; culmen 1.70 or less. 



Adult with basal portion of upper mandible often wrinkled and warty; 

 plumage, at all ages, as in G hyperborea, but young rather lighter in 

 color, with the darker stripes of upper parts less strongly contrasted; 

 length 20.00-26.00, wing 13.75-15.50, culmen 1.50-1.70, tarsus 2.30-3.00, 

 middle toe 1.80-2.05. Hab. Interior of Arctic America in summer; mi- 

 grating south, in winter, to southern California, and eastward to Mon- 

 tana 170. C. rossii (Baibd). Ross's Snow Goose. 



Genus ANSER Brisson. (Page 87, pi. XXVIII., fig. 3.) 



Species. 

 Common Characters.— Plumage brownish, the feathers of back, etc., with 

 lighter tips ; lower parts pale brownish gray or grayish white, becoming pure 

 white on under tail-coverts ; upper tail-coverts white ; tail dusky, tipped with white. 



i References given on page 351 (« Hypothetical List") of the A. 0. U. Check List. It is, however, beyond 

 question a good species. 



