66 NOBTH AMERICAN DUCKS, GEESE, AND SWANS. 



they migrate by the most direct route. Though occurring accidentally 

 in northern Europe and found on the Arctic coast of northeastern 

 Asia, sometimes in considerable numbers, the lesser snow goose is not, 

 as yet, known to breed in the Eastern Hemisphere. 



Winter range. — Both forms of the snow goose occur during the 

 winter season in the lower Mississippi Valley. It seems probable that 

 in this district the Mississippi .River is the approximate dividing line 

 between the two forms, to the westward C. hyperborea being the more - 

 common, to the eastward, O. nivalis. Both forms winter as far north as 

 southern Illinois, .and the lesser snow goose is abundant in winter in 

 Louisiana and Texas, and ranges south in Mexico to Guanajuato and 

 Jalisco, and rarely to northern Lower California. It winters spar- 

 ingly in southern Colorado, more commonly in Utah, abundantly in 

 Nevada, and along the Pacific coast from southern California (Orange 

 County) to southern British Columbia. On the Asiatic side it winters 

 south to Japan. 



Spring migration. — Writing many years ago, Ross states that the 

 lesser snow goose arrives at Great Slave Lake earlier than the greater. 

 Recent records of spring migration confirm this statement, and our 

 present knowledge of isothermal lines affords a satisfactory explana- 

 tion. It is considered that the common species in eastern North 

 Dakota is C. nivalis, while the bird of Montana is G. hyperborea. 

 Long-continued observations in the valley of the Red River of the 

 North indicate 'that the first O. nivalis arrive on the average at lati- 

 tude 47° on April 15; at the same latitude in central Montana the first 

 migrants of 0. hyperborea appear April 6. The more eastern birds 

 advance to Aweme, Manitoba, latitude 50°, April 22, while at this 

 latter date the van has reached Edmonton, Alberta, latitude 54°. Yet 

 these more western and northern birds (lesser snow geese) are actually 

 traveling in warmer weather than their eastern relations migrating at 

 a later date; for during the last third of April the temperature at 

 Edmonton averages about*£ degrees warmer than at Aweme. 



Further advance of the lesser snow goose is recorded during the 

 spring of 1904 to Fort Vermilion, latitude 58°, April 26, and to Fort 

 Simpson, latitude 62°, May 2. East of Fort Simpson at Southampton 

 Island, in Hudson Bay, this same spring the first snow geese were not 

 seen until thirty-three days later — June 4 — while to the westward, at 

 Point Barrow, Alaska, more than 500 miles .farther north, the first 

 lesser snow geese arrive just about the same time as at Fort Simpson. 

 The lesser snow geese that reach their breeding grounds by way of 

 Alaska probably winter at least 800 miles farther north than those 

 of the Mississippi Valley, and spring opens on the Pacific coast much 

 earlier than in the interior. 



The most northern records of the lesser snow goose are on Banks 

 Land, where it arrived at Princess Royal Islands, latitude 73°, May 31, 



