Fox Sparrows – one of the Northwest’s more confusing species

By eBird Northwest Team September 20, 2016
Figure_1

Sooty Fox Sparrow from Humboldt Co., CA 25 Sep 2012. An example of a more reddish and gray faced Sooty.

Four groups of Fox Sparrows occur in our region; few other parts of the country can claim that distinction. Three breed in the region and one is a scarce winter visitant. Each group has a very distinct natural history and is usually identifiable in the field. eBirders should make an effort to record them separately, and thereby contribute measurably to our knowledge of them.  As long as observers are aware that all of them present field identification challenges of varying degrees and exercise some caution in field identification, eBird data should provide useful insights into the fine points of their distribution and changes over time.

Distribution

Sooty Fox Sparrow – an uncommon breeder along the Washington coast from Point Grenville north to Neah Bay and east along the Strait of Juan de Fuca to Sekiu, rarely found more than a mile inland from the beach.  Also breed on small islands in the San Juans:  Smith, Yellow and Sucia. Non-breeding summering birds are very rarely found away from the breeding areas in June through August. Common wintering species in western Washington and Oregon up to the snow line in the Cascades, less common in winter on the east slope of the Cascades and found sparingly in the Columbia Basin, see here.  Common migrant at all elevations east to the Columbia Basin.

Slate-colored Fox Sparrow – Breed on the east slope of the Cascades north of the Columbia River, and occasionally in drier areas just west of the Cascade Crest such as at Mt. St. Helens, in the northeast corner of Washington, and in the Blue and Wallowa Mountains of southeast Washington and northeast Oregon, and south into the higher portions of Malheur County, see here. Spring migrants can be found at low elevation areas on the eastside into early May. Most fall migration is probably at high elevation, but there are some records in the lower areas. Winter reports are few, as their wintering range is in the southwestern states and northern Mexico.

Thick-billed Fox Sparrow – Uncommon breeder in the Siskyous to eastern Curry and on the east slope of the Oregon Cascades to the Columbia River, breeding in Washington is suspected but not documented at a few locations in Klickitat and Skamania counties, see here.  Wintering range is well south of the region, and migration is poorly known.

Red Fox Sparrow – A boreal breeding species that primarily winters east of the Rocky Mountains, but like several other Alaskan breeding species, winters in very low numbers in the western states.  Scarce, but annual in winter in the Northwest, most records are from the Puget Trough and Willamette Valley.

Unknown – Further field work is needed to determine which population nests on Steens Mountain and in the Ochocos.

Identification and eBird validation:

Sooty Fox Sparrow — The default wintering Fox Sparrow throughout most of the Northwest, and a common backyard winter bird in most westside areas.  As common as they are, they still present a few identification challenges including:

  • a wide range of plumage variation between the subspecies;
  • fairly frequent intergradation with Red Fox Sparrow;
  • and confusion with northwest Song Sparrows.

The subspecies that comprise the Sooty group range from almost blackish upperparts that show no pattern to gray and brown upperparts with traces of a face pattern and back striping.

Figure 2. Sooty Fox Sparrow from Neskowin, OR 4 October 2013. A dark chocolate bird from the outer coast.. Note the very dense spotting below and nearly solid dark flanks. The heads of these birds are nearly uniform dusky chocolate brown with very little gray in the auriculars.

Sooty Fox Sparrow from Neskowin, OR 4 October 2013. A dark chocolate bird from the outer coast.. Note the very dense spotting below and nearly solid dark flanks. The heads of these birds are nearly uniform dusky chocolate brown with very little gray in the auriculars.

 

Sooty Fox Sparrow from Sauvie Island, OR 19 Mar 2011. It is sort of middling in color and breast spot density and shows no hint of wingbars. Note how the yellow on bill is getting pale. This is typical of March Sooties.

Sooty Fox Sparrow from Sauvie Island, OR 19 Mar 2011. It is sort of middling in color and breast spot density and shows no hint of wingbars. Note how the yellow on bill is getting pale. This is typical of March Sooties.

Birders who are accustomed to the darker Sooty races are sometimes tempted to call the lighter bird something other than Sooty. The breeding range of Sooty overlaps with Red Fox Sparrow in south central Alaska; intergrades are frequently noted around Anchorage and the upper Cook Inlet area. Winter birds, particularly on the westside, that have some but not most of the Red Fox Sparrow field marks described below are best left as simply unidentified Fox Sparrow. And finally, there is the underrated problem of confusion with the dark northwest races of Song Sparrow, particularly in summer when Song Sparrow plumage is often worn and relatively featureless. Beak shape and color are always useful for separating the two, but the main problem is the mistaken assumption that a bird is simply “too dark” to be a Song Sparrow.

Song Sparrow from Raymond Airport, Pacific County Washington 21 August 2016. Photographed by Brad Waggoner.

Song Sparrow from Raymond Airport, Pacific County Washington 21 August 2016. Photographed by Brad Waggoner.

Slate-colored Fox Sparrow – Relatively subdued in coloration, typical Slate-colored Fox show a relatively unpatterned gray face, crown and back, brownish wings and tail that can show a tinge of rusty, and distinct black, dark brown or brown gray chevrons on their breast and flanks.

Figure 5. Slate-colored Fox Sparrow from Glenwood, Klickitat, WA 26 May 2013.

Slate-colored Fox Sparrow from Glenwood, Klickitat, WA 26 May 2013.

Other than the puzzling altivagans, variously treated as Slate-colored, Red or an intermediate population, they typically show weak or no wingbars. Some of the grayest races of Sooty Fox approach Slate-colored in coloration, but can usually be separated as they still show the messy checkerboard of breast streaking that is characteristic of Sooty, while Slate-colored typically have fewer, neater chest markings that as a rule do not coalesce into a very large central breast ‘blotch’.

Figure 6. Slate-colored Fox Sparrow from Malheur, OR 14 Sep 2015.

Slate-colored Fox Sparrow from Malheur, OR 14 Sep 2015.

Belly markings usually differ, with Sooty showing a buffy wash and brown markings, while Slate-colored is typically whitish with few markings.

Thick-billed Fox Sparrow — Unfortunately, the Oregon races do not exhibit the very large bill that California birds show, making identification more difficult in the Northwest.  Fortunately, they give the same hard, sharp ‘chink’ call note that is characteristic of Thick-billed and very different from the other Fox Sparrow groups.   Otherwise, they strongly resemble Slate-colored in plumage, although their breast streaking tends to be sparser, finer and even more blackish.

Figure 7. Thick-billed Fox Sparrow from Siskiyou Mtns. NW of Cave Junction, Josephine Co., OR 10 June 2012.

Thick-billed Fox Sparrow from Siskiyou Mtns. NW of Cave Junction, Josephine Co., OR 10 June 2012.

Red Fox Sparrow  — Identification, which should be straightforward, is complicated by two issues.

Figure 7. Red Fox Sparrow from South Padre Island, Cameron Co., TX 13 Nov. 2011.

Red Fox Sparrow from South Padre Island, Cameron Co., TX 13 Nov. 2011.

One is intergradation with Sooty in south central Alaska (described above) and second  is the problematic subspecies altivagans.

Figure 8. Presumed P. i. altivagans that was in Eugene, OR 23 Mar 2008. Looks mostly like a Red, but has no gray on the back or rump and a weaker face pattern than a normal Red. Does have wingbars and russet spotting and streaking below.

Presumed P. i. altivagans that was in Eugene, OR 23 Mar 2008. Looks mostly like a Red, but has no gray on the back or rump and a weaker face pattern than a normal Red. Does have wingbars and russet spotting and streaking below.

Since altivagans range appears to be mostly the southern Canadian Rockies and they are likely short-distance north-south migrants, they should not occur regularly in our region, but the Alaska intergrades likely do.  In order to be considered a “countable” Red Fox Sparrow, most or all of the following field marks should be evident on a bird: strong rusty and gray face and crown pattern, conspicuous rusty and gray striping on the back, two narrow white wing bars on rusty wings, rusty underpart streaking, and bright rusty tail and wings contrasting with a gray rump.

FOSP Table

References:

Birdfellow.  http://www.birdfellow.com/birds/fox-sparrow-passerella-iliaca#/

Gillson, G.  2003. Fox Sparrow ID.   http://thebirdguide.com/fox/fox.htm

Marshall, D.B., M.G. Hunter and A.L. Contreras. 2003.  Birds of Oregon: A General Reference. Oregon State University Press.  Corvallis, OR. 768 Pp.

Patterson, M.  2012.  It is complicated. http://www.surfbirds.com/community-blogs/northcoastdiaries/?p=756

Rising, J.D. 1996. A Guide to the Identification and Natural History of the Sparrows of the United States and Canada.  Academic Press.  San Diego, CA.  365 Pp.

Roberson, D.  Fox Sparrow Forensics.  http://creagrus.home.montereybay.com/MTYbirdsFOSP.html

Wahl, T.R., B. Tweit and S.G. Mlodinow. 2005.  Birds of Washington: Status and Distribution.  Oregon State University Press.  Corvallis, OR. 436 Pp.

Weckstein, J.D., D.E. Kroodsma and R.C. Faucett.  2002.  Fox Sparrow (Passerella iliaca).  In The Birds of North America, No. 715 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.

Text by Bill Tweit, photos and captions by Dave Irons.