472 ANIMAL LIFE IN THE YOSEMITE 



was sunk in the dead grass of the previous season's growth, but was above 

 the level of the sod proper, the extreme bottom of the structure barely 

 touching the ground. The nest had been built at the base of a leaning 

 willow stem. Three inches above it, another stem formed a sort of ridge- 

 pole, supporting a canopy of last year 's grasses. These had to be parted 

 in order to permit the observer to look down into the nest cavity. The 

 nest was constructed exteriorly of coarse grasses woven into a loose frame- 

 work ; the interior lining consisted solely of dried and yellowed grass 

 stems of the finest »ort. There were five eggs, with a pale greenish blue 

 ground color, rather heavily marked vnth irregular spots of light reddish 

 brown. Incubation was found to have proceeded about halfway toward 

 hatching. 



Fox Sparrows. Passerella iliaca (Merrem)^^ 



Field characters. — Of chunky build, between Eobin and Jimeo in size. Upper surface 

 almost uniform dark bro\\Ti, grayish, or reddish in tone, according to subspecies; wings 

 and tail in any case with more or less of a foxy red tinge; under surface white, with 

 bold triangular spots of dark brown or grayish brown, most numerous on fore neck 

 (pi. 48a); no white markings on either wings or tail; bill varyingly stout, dark-colored, 

 in some races yellow below at base. Voice : Of both sexes, a loud sharp single call note, 

 clinli ; song of male notably clear and melodious in quality. 



Occurrence. — Common in summer in Canadian Zone on both slopes of Sierra Nevada, 

 ranging down to 5500 feet altitude, as near Chinquapin, and up to more than 8000 feet, 

 as at Porcupine Flat. Also, in different subspecific forms, a migrant and winter visitant, 

 rare in Lower Sonoran Zone, but common in Upper Sonoran and (except during periods 

 of heavy snows) Transition zones, throughout the region. Inhabits thick brush, under 

 which it industriously forages with much sound of scratching in the dry litter; found 

 singly or in pairs, never in flocks. 



31 The eight subspecies of Fox Sparrow which occur in the Yosemite region differ 

 in varying degree from one another in one or more characters. Some of these minor 

 points of discrimination cannot be seen except by close examination of specimens in 

 hand, but others are determinable even in the field. For example, even a novice, remain- 

 ing in the region throughout the year, could recognize the differences between the gray- 

 backed birds of summer ^^ith big bills {mariposae and monoensis) and the brown-backed 

 subspecies of winter with medium-sized or small bills (unalaschcensis, sinuosa, insularis, 

 and altivagans). Schist acea is a gray -backed winter visitor with very small bill. 

 Megarhyncha is gray-backed, with large but relatively short bill, and of rare occurrence 

 in early winter. Such data as we have do not show any regularity or restriction in the 

 occurrence of these different wintering subspecies. Probably all of them could be 

 recorded in any one of a number of localities on the west slope, were collecting extended 

 over a suiBcient period of time. 



The names and ranges of the birds occurring in the region at different seasons of 

 the year are given in the following paragraphs. For the criteria of discrimination be- 

 tween these races we must refer the reader to the detailed account of the Fox Sparrows 

 given elsewhere by Swarth (Univ. Calif. Publ. Zool., 21, 1920, pp. 75-224, pis. 4-7, 30 

 figs, in text). 



Shumagin Fox Sparrow^ Passerella iliaca unalaschce7isis (Gmelin), winter visitant 

 to west slope of Sierra Nevada; found by us from Snelling (250 feet altitude) to 

 Yosemite Creek (at 7800 feet). Earliest record, at latter locality, October 6, 1915. 

 Summers on Alaska Peninsula and nearby islands. 



Kadiak Fox Sparrow, Passerella iliaca insularis Eidgway, winter visitant to west 

 slope of Sierra Nevada; found by us from El Portal (2000 feet) to near top of Yosemite 

 Falls (6500 feet). Earliest record, October 14 (1915), from Aspen Valley (6400 feet). 

 Summers on Kadiak Island, Alaska. 



