464 ANIMAL LIFE IX THE YOSEMITE 



among the low branches of an adjacent conifer, repeating their call notes 

 with an intonation which suggests extreme anxiety. 



After the broods are reared the adults continue to guard and care for 

 their charges for some time; in some eases, at least, the family stays 

 together through the fall molt. From this initial grouping it is but a step 

 to the formation of the flocks in which the birds spend the winter. Flock 

 formation persists until the birds seek their nesting grounds again the 

 following spring. 



From late April until July pairs are the rule. Then young begin to 

 appear in numbers and family parties are of common observation. Such 

 groups were seen at Merced Lake on August 23, and in Yosemite Valley 

 even as late as September 24 (1915). Flock formation is under way about 

 the latter date; one band of 20 w^as seen in Yosemite Valley on Septem- 

 ber 25, and several of 20 to 50 each in Tioga Pass, September 28, 1915. 

 The flocks hold together through the winter months, sometimes becoming 

 mixed with those of Chipping Sparrows in the valleys, but more often 

 keeping by themselves. At Pleasant Valley on February 27 and 28, 1916, 

 bands of 12 to 35 were seen; and a flock of 15 was observed in Yosemite 

 Valley on February 29 the same year. By April 27, the time of our next 

 visit, the low^lands were cleared of juncos, and the birds seen in Yosemite 

 Valley on April 28, 1916, Avere not in flocks. On May 14, 1919, juncos 

 at Hazel Green w^ere paired and the males were trilling their songs. 



Bell Sparrow^. Amphispiza belli (Cassin) 



Field characters. — Size of Juneo or Linnet; tail as long as body. Upper surface 

 plain dull brown, becoming iron gray on head ; area in front of eye, and conspicuous 

 stripe down side of neck from bill, black (pi. 8i) ; spot on each side of brow, lower cheek, 

 and throat and under surface of body, white; a distinct black spot on center of breast. 

 Voice: Song of male a set utterance of tinkling quality, tweesitity-slip, tweesiiity-sJip, 

 swer; also a faint one-syllabled call note, sect. 



Occurrence. — Common resident in Upper Sonoran Zone over western base of Sierras. 

 Lives almost exclusively in greasewood chaparral. Observed by us at Pleasant Valley, 

 near Coulterville, and near El Portal. To be seen in pairs or scattered family parties. 



The Bell Sparrow is closely associated with that type of chaparral, 

 made up almost purely of the greasewood, which clothes so much of the 

 dry foothill country flanking the west base of the Sierra Nevada. Since 

 this is a bird of dull colors and retiring habits, it will not likely be seen 

 by a person passing quickly along any of the dusty roadways through 

 this 'chamisal.' The bird student interested in forming an acquaintance 

 with this si)arrow will need to tarry at some place in the foothills and 

 spend a few hours amid the greasewood itself. 



