Fox Sparrow

Bird of the Month: Fox Sparrow

By Hugh Jennings

PC: Mick Thompson (Fox Sparrow)

PC: Mick Thompson (Fox Sparrow)

Scientific Name: Passerella iliaca

Length 7 in

Wingspan 10.5 in

Weight: 1.1 oz

AOU Band code FOSP

The genus name Passerella (pass-er-EL-ah) is from Latin, passer, meaning a sparrow. The species name iliaca (eye-lih-AY-cah) is Latin relating to the marked flanks. The common name is from the reddish or tawny “fox” color of feathers. The Fox Sparrow (FOSP) is about 7” long with a wingspan of 10.5” and a weight of 1.1 oz. (32g). It is one of our largest sparrows.

Two races of the Fox Sparrow have breeding populations in Washington. The “Sooty” is a medium brown and is found on the outer Olympic Peninsula from May to late September and is a common western lowland resident from October to March. The “Slate-colored” is fairly common in mid-elevation slopes of the Cascades from May to mid-October and a rare eastern Washington resident from mid-October through April. A few reports of the Red Fox Sparrow (probably western subspecies zaboria ) in winter, during passage.

It is considered likely that the FOSP will soon be split into two or more species. In general, the sparrow has whitish underparts boldly streaked with brown or rufous and with an irregular central spot on the breast, and a reddish-brown rump and tail. The coloring varies geographically. The Pacific NW (Sooty) bird has  dark brown head and back; the western mountain FOSP (Slate-colored) has gray head and back. The eastern United States subspecies has rufous streaking on its gray head and back.
The FOSPs are found in dense brush and riparian thickets during breeding season. During migration and in the winter they are usually in dense brush in open and forested habitats.

Its song is a short series of clear melodious whistles that are more melodic than other sparrows. The call is a sharp smack or chuck. 
They feed on the ground, eating seeds, fruits and insects. It often jumps forward and back, pulling aside ground debris to get at the food underneath. They may come to feeders where seed is scattered on the ground.

The nest is cuplike and made of grasses, lichens, and leaves lined with hair, fur and rootlets. The nest is built on the ground under a small tree or shrub. There are 4-6 light blue-green eggs with darker marks. The incubation period is 11-14 days and the young fledge 7-12 days later. There may be two broods in one year. The young are altricial, i.e., dependent on the parents for food and warmth, and stay in the nest.