124 BIRDS OF THE ROCKIES 



as to their movements in the migrating season. Do 

 those on the western side of the mountains travel over 

 the towering summits from the eastern plains ? Or do 

 they come up from their southern winter homes by way 

 of the valleys and plains west of the range ? Undoubt- 

 edly the latter is the correct surmise, for there were 

 birds at Glenwood that are never known to ascend far 

 into the mountains, and should they attempt to cross 

 the Divide in the early spring, they would surely perish 

 in the intense cold of those elevated regions, where 

 snow often falls even in June, July, and August. One 

 can easily imagine some of the eastern and western 

 residents meeting in the autumn on the plains at the 

 southern extremity of the mountain range, dwelling 

 together in some southern locality throughout the 

 winter, and then, when spring approaches, taking their 

 separate routes, part going east and part west of the 

 range, for their breeding haunts in the North. More 

 than likely they do not meet again until the following 

 autumn. There are individuals, doubtless, that never 

 catch a glimpse of the western side of the great Ameri- 

 can watershed, while others are deprived of the priv- 

 ilege of looking upon the majestic panoramas of the 

 eastern side. 



What has just been said applies, of course, only to 

 those species that prefer to dwell in the lower altitudes. 

 There are other species that find habitats to their taste 



