Original description: Emberiza unalaschcensis Gmelin 1789
Taxonomic history in AOU/AOS Check-list
AOU 1 (1886): Townsend’s Sparrow, Passerella iliaca unalaschcensis
AOU 2 (1895): Townsend’s Sparrow, Passerella iliaca unalaschcensis
AOU 3 (1910): Shumagin Fox Sparrow, Passerella iliaca unalaschcensis; Sooty Fox Sparrow, Passerella iliaca fuliginosa; Kadiak Fox Sparrow, Passerella iliaca insularis; Townsend’s Fox Sparrow, Passerella iliaca townsendi
AOU 4 (1931): Shumagin Fox Sparrow, Passerella iliaca unalaschcensis; Kodiak Fox Sparrow, Passerella iliaca insularis; Valdez Fox Sparrow, Passerella iliaca sinuosa; Yakutat Fox Sparrow, Passerella iliaca annectens; Townsend’s Fox Sparrow, Passerella iliaca townsendi; Sooty Fox Sparrow, Passerella iliaca fuliginosa
AOU 5 (1957): Fox Sparrow, Passerella iliaca unalaschcensis, Passerella iliaca insularis, Passerella iliaca sinuosa, Passerella iliaca annectens, Passerella iliaca townsendi, Passerella iliaca fuliginosa
AOU 6 (1983): Fox Sparrow, Passerella iliaca
AOU 7 (1998): Fox Sparrow, Passerella iliaca [unalaschensis group, Sooty Fox Sparrow]
IUCN Conservation Status: Of least concern
The habitats used by the Sooty Fox Sparrow are not believed to have been affected recently by human activity.
Habitat: Wintering birds in most areas show a preference for damp habitats, frequenting tall, dense thickets along creeks and streams. In British Columbia and Washington, Himalayan blackberry thickets are especially attractive to this species. California winterers are also found in dense woody chaparral. Breeders also prefer damp, dense cover, including lush willows, alders, and brambles on the shores of lakes and ponds.
Behavior: Large and noisy, the Sooty Fox Sparrow often feeds on the ground in the open. When it is perched in heavy cover, this species often responds with apparent curiosity to squeaking noises, mounting to the top of a brush pile or a bare twig at mid-height to investigate their source. They are not especially social, but in urban parks in the Pacific northwest, half a dozen or more may feed in close association in migration and winter, often in association with Spotted Towhees, Song Sparrows, or Golden-crowned Sparrows.
Sooty Fox Sparrows are relatively powerful fliers, at least over short distances; they are rarely seen in sustained flight of more than a few yards. The wing beats of fleeing birds are strong and fast, and the broad tail is not pumped, as in the Song Sparrows, but twitched from side to side.
Migrants and breeders sing from low to medium-height perches in thickets and fairly open forest.
Voice: The Sooty Fox Sparrow is the boldest of its genus, fearlessly emerging from tangled cover to kick and scratch vigorously through grass and leaf litter in yards and parks. If disturbed, birds hop or fly in low swooping flight back into brambles or other low dense vegetation, where they may perch in sight as they give a square, harsh, anxious-sounding tchak, louder and lower-pitched than the tek note of a Lincoln Sparrow or junco; this call is very similar to the corresponding note given by the Red and Slate-colored Fox Sparrows. A prolonged, fairly sweet seeb note, with slow attack and decay, is given from a perch or in flight; it is fuller, longer, and more clearly ascending than the corresponding, slightly wavering call of the White-throated Sparrow.
The loud, melodious song of the Sooty Fox Sparrow is given both in migration and on the breeding grounds; it can be heard, too, on bright, warm winter days when most other birds are silent. It often comprises four phrases: the first is a hesitant introduction of short, sharp, usually well-separated notes; the second is a series of two or three higher-pitched whistles; the third is a parallel series of lower-pitched whistles with a buzzy undertone; and the concluding phrase is variable, sometimes a descending slur and sometimes a dry trill. The entire song seems lower-pitched, fuller, and hoarser than the sweeter, more musical phrases of the Red Fox Sparrow, though the race zaboria of the latter species may sing more harshly than Red Fox Sparrows breeding farther east.
Detailed description and measurements drawn from standard reference works
Adult Passerella unalaschcensis fuliginosa: Tail feathers and upper tail coverts brown with slight rusty tinge. Rump, back, nape, sides of head, and crown unstreaked dull dark sooty brown. Primaries and secondaries dark sooty brown with very faint rusty tinge, inner webs colder and paler brown. Tertials slightly rustier. Greater coverts with dark centers and broad dull rusty edges. Median and lesser coverts dull dark sooty brown, darker at center. Nape dull dark sooty brown.
Under tail coverts dull brown with slightly paler brownish edges. Vent, belly, and breast dull off-white, heavily marked. Flanks and sides of lower breast nearly solid dark sooty brown. Underparts densely and irregularly marked with large blackish brown spots and chevrons, heaviest on the breast. Throat off-white, heavily spotted and speckled blackish brown except at center. Throat separated from short and inconspicuous off-white jaw stripe by short, thick, poorly defined lateral throat stripe.
Crown sooty brown. Ear coverts finely streaked with dull off-white. Lores with fine off-white shaft streaks. Inconspicuous supercilium slightly grayer sooty brown, extending from bill to nape.
Tarsus and toes dull pinkish brown. Rather long, sharp-pointed bill bright orange-yellow on lower and edges of upper mandible; rest of upper mandible dark gray.
Juvenile Passerella unalaschcensis fuliginosa: Similar to adult, but with only very slight or no rusty tinge on tail and upper tail coverts. Off-white ground color of underparts replaced with pale yellowish buff.
Length 160-173 mm (6.3-6.8 inches)
Wing chord 77-86 mm (3.0-3.4 inches)
Tail 72-78 mm (2.8-3.1 inches)
Mass 36 grams
Adult Passerella unalaschcensis unalaschcensis: Tail feathers and upper tail coverts warm brown. Rump, back, and scapulars plain brown. Primaries and secondaries dull cinnamon, inner webs paler cinnamon-brown. Tertials dull cinnamon. Greater coverts with dark centers and broad dull cinnamon edges. Median and lesser coverts dull cinnamon-brown, darker at center. Nape pale gray to gray-brown.
Under tail coverts gray-brown with broad whitish edges. Vent, belly, and breast white, heavily marked. Flanks and sides of lower breast mostly grayish brown. with streaks and hint smudge. Underparts densely and irregularly marked with large grayish brown spots and chevrons, heaviest on the breast. Throat white, rather sparsely spotted and speckled brown, more faintly at center. Throat separated from short, gray-flecked white jaw stripe by short, thick lateral throat stripe.
Crown grayish brown. Side of neck clear gray. Ear coverts brownish gray, finely streaked with off-white. Lores with fine off-white shaft streaks. Long bright supercilium gray, extending from bill to nape.
Tarsus and toes brown. Rather long, sharp-pointed bill yellowish or pinkish on lower and edges of upper mandible; rest of upper mandible dusky.
Juvenile Passerella unalaschcensis unalaschcensis: Similar to adult, but browner above, with pale feather edges and dark shaft streaks. White ground color of underparts replaced with pale yellowish buff; heavily streaked dusky below. (15)
Length 157-170 mm (6.2-6.7 inches)
Wing chord 80-86 mm (3.1-3.4 inches)
Tail 69-76 mm (2.7-3.0 inches)
Mass 36 grams