382 U.S. NATIONAL MUSEUM BULLETIN 23 7 part x 



these leucostictes occur in winter in immediately adjacent parts of 

 New Mexico, casually in Wyoming, and possibly in Utah. 



The descent to the lower ranges begins in late September and 

 becomes pronounced when the first severe autumn snows strike the 

 peaks. Through October and November, as the storms increase in 

 severity and frequency, flocks of from 50 to more than 100 rosy 

 finches begin to appear in the foothills. At Rocky Mountain National 

 Park small bands composed entirely of australis arrived in the Transi- 

 tion Zone at 8,500 feet in mid-October; usually they do not remain 

 then, but move higher again after the snow that prompted their first 

 descent has melted. The November storms, however, produce 

 permanent snows on the alpine meadows, and thereafter many of the 

 birds either stay in the Transition Zone "parks," or descend into the 

 foothills. Even at that season small flocks may be found above 

 timberline, and a number return to the summits in winter whenever 

 the weather clears after storms. 



Niedrach found the species common during the entire winter of 

 1918 at 13,000 feet on Quartz Creek, at the edge of Taylor Peak, 

 Pitkin County. The birds appeared in bands of three or four to a 

 dozen, searched the newly turned soil of excavations for food, and ate 

 refuse the cook threw out. Horace G. Smith, of Denver, told me that 

 these finches were often present in large flocks in winter near mines 

 high in the mountains, where they frequented the places where the 

 cooks disposed of dishwater containing crumbs and other food. 



In late October three other species of leucosticte arrive in Colorado 

 from their summer ranges and join the brown-capped rosy finches to 

 form mixed flocks which may number a thousand birds, though groups 

 of one or two hundred are more usual. The gray-crowned rosy finch 

 (L. t. tephrocotis) soon becomes the most common form, almost equaled 

 by australis. Hepburn's rosy finch (L. t. litioralis) is fairly numerous, 

 often making up a quarter of the total, while the black rosy finch 

 {L. atrata) is always rather rare, seldom represented by more than one 

 or two individuals. These flocks consist entirely of leucostictes; 

 no other birds mingle with them in the meadows. Sometimes a small 

 flock is comprised entirely of australis^ but this is not always the rule. 



Every mountain storm drives the birds to lower elevations. Severe 

 blizzards bring thousands to the foothills, where they remain as long 

 as the inclement weather lasts. When the weather clears, many 

 follow the receding snowline back into the higher country; others 

 remain for some weeks in the valleys, whUe still others make a daily 

 trek in clement periods to elevations 2,000 to 3,000 feet above their 

 roosting sites. If the fair weather is prolonged, a number return to 

 the alpine tundra until the next storm drives them down again. 

 Aiken writes (Ridgway, 1875) : "A storm gathers them into a dense 



