No. 602] SHORTER ARTICLES AND DISCUSSIONS 



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and bushes even where it ranges well below timberline. It feeds 

 winter and summer upon seeds of dwarfed vegetation, including 

 those of grass and herbs of various sorts. As far as I can see, 

 its food and feeding habits are identical with those of such other 

 fringillids as goldfinches and siskins. Yet the leucosticte, by 

 the same tests as were used with the cony, is beyond any conten- 

 tion limited downward by an increase of temperature. We find 

 the bird to possess various adaptive features in common with cer- 

 tain arctic finches, such as tufts of bristle-like feathers over the 

 nostrils to prevent fine snow from entering. These enable the 

 bird to spend the long winter on the cold wind-swept ridges, but 

 at the same time would hardly prevent the bird's dropping to 

 warmer climes if the heat were not a strongly deterrent factor. 



Cases of coincidence, as instanced by that of the cony and 

 leucosticte, among animals of widely different powers of locomo- 

 tion and ecologic position, are the rule, not the exception, and 

 impel the observer to belief in the efficacy of the controlling fac- 

 tor above mentioned. 



The Case of the Redwood Chipmunk 

 The redwood chipmunk {Eutamias townsendi ochrogeni/s) is 

 an animal confined to a very narrow but exceedingly long dis- 

 tributional area extending south from the Oregon line as far as 

 Freestone, Sonoma County. Throughout this belt it is conspicu- 

 ously numerous, and is usually the only species of chipmunk 

 present, so that the limits of its range have been easy to mark 

 definitely along the several lines explored. This rodent, by 

 various geographic tests similar to those I have recounted for 

 other birds and mammals, is clearly delimited away from the 

 coast at the bounds of the well-known fog-belt to which the red- 

 wood tree and numerous other plants as well as animals belong. 

 The chipmunk, however, depends in no way upon the redwood 

 or any other one plant species as far as I can see, but feeds 

 upon a great variety of seeds and fruits, like many of its con- 

 geners elsewhere. 



That temperature is also a delimiting factor is shown in parts 

 of the range of the redwood chipmunk. But atmospheric humid- 

 ity or cloudiness or rainfall, factors which I have in this case 

 failed to dissociate, together constitute or include the chief 

 controls. 



