428 ANIMAL LIFE IN TEE YO SEMITE 



Sierra Crossbill. Loxia curvirostra bendirei Ridgway 



Field characters. — Somewhat larger than Juneo but of more chunky build. Head 

 large appearing; tail small, short, and decidedly notched at end. Bill heavy, mandibles 

 much curved, and crossed near end (whence the common name). (See fig. 51.) Body 

 plumage dark gray, variously tinged with greenish, orange or red (see below). Flight 

 undulating, goldfinch-like. Foice : Call notes, sup or chup, usually uttered in three's, 

 and most often given as the birds take wing or fly from place to place. 



Occurrence. — Moderately common resident in the Boreal region (Upper Transition, 

 Canadian, and Hudsonian zones) on both slopes of Sierra Nevada. Observed at several 

 stations, from Hazel Green east to Mono Mills. Also reported to visit Smith Creek, 

 6 miles east of Coulterville, in fall and spring (D. D. McLean). Frequents cone- 

 bearing trees usually far above gi-ound; occasionally forages on ground. Seen by 

 us in small parties of a dozen or less, sometimes in company with other finches. 



The Sierra Crossbill is the local representative of a species which is 

 found throughout the more boreal parts of the northern hemisphere. In 

 our latitude in summer it is an inhabitant of the mountains, and it quite 

 likely remains there through the winter as well, though flocks may some 

 years descend in the latter season to the foothills and valleys. It is 

 impossible to predict with certainty concerning its appearance at any 

 one time in a particular locality ; for its local occurrence varies with the 

 changes in food conditions. Nor, as regards the Yosemite region, can 

 any definite information be given relative to the time or place of its nesting. 



The Sierra Crossbill is likely to be encountered at one time or another 

 at almost any place in the upper part of the Yosemite region. Our first 

 definite record of the occurrence of the species came on September 28, 

 1915, when three of the birds were seen on Tuolumne Meadows. Others 

 were noted at the same place on September 29, and near Glen Aulin on 

 the latter date. Four were seen near Mono Mills on June 10, 1916. At 

 Hazel Green on May 14 and 15, 1919, the species was relatively common, 

 and it was noted once near Tamarack Flat, on May 24, 1919. On each 

 of the dates mentioned the birds came to notice at close range and appeared 

 to be relatively unwary. The irregularity of their observance must be 

 attributed not to shyness, but, first, to their habit of foraging high above 

 the ground, near the summits of lofty trees, where their presence may 

 be altogether unsuspected, and second, to their propensity for wandering. 



The plumage of the male crossbill, as exhibited by a series of specimens, 

 shows much variation in coloration. It is generally assumed that as the 

 birds increase in age they acquire, at successive molts, more and more red 

 in the coloration; but tliis supposition remains to be proved. Male birds, 

 which by dissection are shown to be in breeding condition and hence mature 

 in the generally accepted sense of the word, exhibit a wide range of color- 

 ation, from greenish yellow through orange to brilliant red. The bright 



