Sooty Fox Sparrow

The sooty fox sparrow (''Passerella (iliaca) unalaschcensis'') contains the darkest-colored taxa in the genus ''Passerella''. It is currently classified as a "subspecies group"Not defined by the ICZN within the fox sparrow pending wider-spread acceptance of species status. It has long been suspected to be a separate evolutionary lineage due to morphological distinctness (Swarth 1920), and this is confirmed by analysis of mtDNA sequence and haplotype data (Zink 1994, Zink & Kessen 1999, Zink & Weckstein 2003). This group appears to be most closely related to the thick-billed and/or slate-colored fox sparrows (Zink 1996, Zink & Weckstein 2003).

Description

The sooty fox sparrow complex varies clinally in intensity of color. The upperparts and head are a variable shade of brown, with streaks on the underparts of the same color. The northernmost birds are sandy brown, while southernmost birds are a dark coffee-like color. Sooty fox sparrows prefer to breed in willows and alders at the edge of wet habitats. Beadle and Rising (2003) describe their call note as a sharp ''zitt'' or ''thik'', while Sibley (2000) says it is a loud smack like that of the red fox sparrow.

Subspecies

Six subspecies are usually recognized in the sooty fox sparrow complex, ranging from ''unalaschensis'' in the Aleutians to ''fuliginosa'' in extreme northwestern Washington:

* ''unalaschcensis'' (Gmelin, 1789):
:Breeds from Unalaska Island (in the Aleutian Islands) to the Shumagin and Semidi Islands and the adjacent Alaska Peninsula. Winter range from southern British Columbia to southernmost California, rarely even further south. (Weckstein ''et al.'' 2002)
:There are two distinct groups known from the winter range: brownish ash-gray birds with a longer and more pointed bill, and darker lead-gray birds with a thicker, blunter bill; the taxonomic significance of this is unknown. (Weckstein ''et al.'' 2002)
:Seems to intergrade with ''sinuosa'' and ''insularis'' where their ranges meet. (Swarth 1920)

* ''townsendi'' (Audubon, 1838):
:Breeds along the Pacific Coast from Glacier Bay to Haida Gwaii. Winter range south of breeding range, to central California. (Weckstein ''et al.'' 2002)
:Much darker and more rufous than ''unalaschcensis'', with conspicuously larger and more plentiful breast spots similar to ''fuliginosa''. (Swarth 1920)

* ''fuliginosa'' Ridgway, 1899:
:Breeds on the mainland south from the Stikine River to northwestern Washington. Winter range from southwestern British Columbia south to coastal central California. (Weckstein ''et al.'' 2002)
:Darker and sootier than ''townsendi'', with the largest and most plentiful breast spots. (Weckstein ''et al.'' 2002)

* ''annectens'' Ridgway, 1900:
:Breeds along the Pacific Coast from northern Yakutat Bay to Cross Sound. Winter range in coastal central California. (Weckstein ''et al.'' 2002)
:Intermediate between ''sinuosa'' and ''townsendi''. (Swarth, 1920)
:Morphology and range suggest its validity should be checked out.

* ''insularis'' Ridgway, 1900:
:Breeding limited to Kodiak Island. In winter, found along the Pacific Coast southwards to southernmost California.(Weckstein ''et al.'', 2002)
:Brighter and more uniformly ruddy above, with strong and rich brown breast spots; undertail coverts tinged buff. (Weckstein ''et al.'' 2002)

* ''sinuosa'' Grinnell, 1910:
:Breeds around Prince William Sound and the Kenai Peninsula and on Middleton Island. In winter, south along the Pacific slope of southern California. (Weckstein ''et al.'' 2002)
:Intermediate between ''unalaschcensis'' and ''insularis'', but bill markedly more slender than in either. (Weckstein ''et al.'' 2002)

* ''chilcatensis'' Webster, 1983:
:The "non-typical ''fuliginosa''" of Swarth (1920), breeding between the Chilkat River area to Tewart and surroundings (British Columbia) and wintering along the coast, mainly between Oregon and the San Francisco Bay region. (Weckstein ''et al.'', 2002)
:Much like ''fuliginosa'', but duller and shorter-tailed.
:Not usually accepted as distinct by recent reviewers (e.g., Zink 1994, Rising & Beadle 1996, Zink & Kessen 1999), although the presence of similarly distinct birds in ''unalaschcensis'' suggests the matter warrants more research.

References

* Beadle, David & Rising, Jim D. (2003): ''Sparrows of the United States and Canada : the photographic guide''. Princeton University Press, Princeton. p. 174
* Rising, Jim D. & Beadle, David (1996): ''A Guide to the Identification and Natural History of the Sparrows of the United States and Canada''. Academic Press, San Diego.
* Sibley, David Allen (2000): ''The Sibley Guide to Birds''. Alfred A. Knopf, New York.
* Swarth H. W. (1920): Revision of the avian genus ''Passerella'' with special reference to the distribution and migration of the races in California. ''University of California Publications in Zoology'' 21: 75–224.
* Weckstein, J. D.; Kroodsma, D. E. & Faucett, R. C. (2002): Fox Sparrow (''Passerella iliaca''). ''In:'' Poole, A. & Gill, F. (eds.): ''The Birds of North America'' 715. Academy of Natural Sciences, Philadelphia, PA & American Ornithologists' Union, Washington, D.C. Online version, retrieved 2006-11-27. (requires subscription)
* Zink, R. M. (1994): The Geography of Mitochondrial DNA Variation, Population Structure, hybridization, and Species Limits in the Fox Sparrow (''Passerella iliaca''). ''Evolution'' 48(1): 96-111. (HTML abstract, first page image)
* Zink, Robert M. & Kessen, A. E. (1999): Species Limits in the Fox Sparrow. ''Birding'' 31: 508–517.
* Zink, Robert M. & Weckstein, Jason D. (2003): Recent evolutionary history of the Fox Sparrows (Genus: ''Passerella''). ''Auk'' 120(2): 522–527. rticle in English with Spanish abstract DOI: 10.1642/0004-8038(2003)120 522:REHOTF.0.CO;2HTML fulltext
(without images)

{{Taxonbar, from=Q7562787

sooty fox sparrow
Native birds of Alaska
Native birds of Western Canada
Native birds of the Northwestern United States
sooty fox sparrow
Taxa named by Johann Friedrich Gmelin