Passerella iliaca
Order Passeriformes
Family Passerellidae
Adult.— Top of head and back reddish-brown and gray; tail reddish-brown; sides of throat and breast thickly marked with bright reddish-brown spots, forming a heavy blotch in the centre of the breast; belly and sides marked with dark brown arrow-shaped spots.
The Fox Sparrow is a common migrant through New York and New England from the middle of March to the end of April, and from the middle of October to the end of November. The bushes along the edges of cultivated fields and open places in woods are the resort of this large and handsome sparrow. When a flock of Fox Sparrows are startled from the ground, they generally fly into a tree, one after another, instead of diving headlong into cover after the manner of their frequent companions the Song Sparrow. The rich tawny color of the back and head, and particularly the reddish-brown tail, are then conspicuous. When seen on the ground, the large arrow-shaped markings on the white breast and flanks are prominent. When on the ground, they scratch with both feet at once, jumping forward and back, often making a noticeable rustling among the leaves. Often the little flocks which we meet are silent, but sometimes they sing freely.
The song is loud and rich, one of the finest of sparrow songs; there is a suggestion of generosity and courage in the manner of its delivery and the fullness of its tone; it is occasionally heard in the autumn. The ordinary call-note is a st, similar to that of the Song Sparrow and the White-throat, but slightly heavier. The bird also utters a chuck of alarm.
The fox color should distinguish this sparrow from the others. Certain Song Sparrows, especially those seen in early spring, are so unusually reddish brown on the upper parts, that a beginner might be puzzled to decide whether they were Song Sparrows or Fox Sparrows, but as in many similar cases, a doubtful Fox Sparrow is probably a spurious one; the genuine Fox Sparrow is so very tawny that, when he really appears, no doubt of his identity is left in the mind. The White-throated Sparrow’s period of migration slightly overlaps the Fox Sparrow’s, both in April and October, but the tail of the former is grayish-brown. The Fox Sparrow is not infrequently mistaken for the Hermit Thrush; the tail is reddish-brown in both birds, but the back and head of the Thrush and his breast-markings have none of the rich tawny color of the Sparrow.
Hoffmann – A Guide to the Birds of New England and Eastern New York (1904)