The Oregon Juncoes 



TakerTin Washing^ 

 Pholo'_by the A uihor 



the West by reason of varied 



conditions and insufficient 



data. The theory is that 



Ik. the birds are 



still following 

 the retreat of 

 the glacial ice. 

 We know that 

 the glacial ice- 

 sheet, now 

 confined to 

 Greenland 

 and the high 

 North, once 

 covered half 

 the continent. 

 In our own 

 mountains we 

 see the ves- 

 tigial traces of 

 glaciers which 

 were once of 

 noble propor- 



1 1 on s 



W 



XEST AND EGGS OF COUES JUNCO 



know that the 

 southward 

 advance of the 



continental ice-sheet must have driven all animal life before it; and, like- 

 wise, that the territory since relinquished by the ice has been regained by 

 the animals. What more natural than that we should witness through 

 close observation the northward advance of those varieties of birds which 

 are best suited to withstand cold, and the corresponding occupation of 

 abandoned territory on the part of those next south? 



Juncoes, moreover, are erratic in their migrations; and in the West, 

 at least, tend to become non-migratory. While Oregon Juncoes are the 

 common winter birds of Puget Sound, Coues' (or Thurber's) are not 

 entirely absent at this season, and we may even look to see them presently 

 hold their own throughout the year. The problem is further complicated 

 by what we call vertical migration, by which is meant that mountain 

 birds descend to the valleys in winter, instead of flying southward. 

 Winter "couesi," therefore, may or may not be strictly resident at, say, 

 Camp Lewis, near Tacoma. The summer birds of that region may be 



2<?0 



