Tuesday, January 22, 2013

Song Sparrow or Fox Sparrow?

Rusty Song Sparrow ID
Song Sparrow ("Rusty" form), Beaverton, Oregon. 21 January, 2013 by Greg Gillson.
The following discussion pertains to separating the Rusty Song Sparrow found west of the Cascades in the Pacific Northwest from the Sooty Fox Sparrow, a wintering species that breeds in coastal Alaska and southward through western British Columbia, sparsely to the Olympic Peninsula of Washington.

This discussion is less apt for Song Sparrows east of the Cascades, and does not apply to summer breeding Fox Sparrows--Thick-billed Fox Sparrows in the Oregon Cascades and southward into SW Oregon and NW California, nor the Slate-colored Fox Sparrow of the Washington Cascades, Great Basin ranges, and Rocky Mountains. [See footnote.]

Both Song Sparrow and Fox Sparrow are found across the North American continent and are highly variable. Beginners are often confused by sparrows, in general. Even experienced visitors from out of the region are frequently confused, as our Song and Fox Sparrows look quite different from these species elsewhere.

The identification of sparrows requires paying special attention to and learning the names of the feather tracts on the head. [See "Advanced birding means learning the basics."]

Sooty Fox Sparrow ID
Fox Sparrow ("Sooty" form), Forest Grove, Oregon. 8 December 2007 by Greg Gillson.
These are the two darkest and rusty-brown colored streak-breasted sparrows in the Pacific Northwest. Here's a quick-glance way of separating them. The head of Song Sparrow (photo below) is gray with rusty brown stripes. The bill is dark gray. This is in contrast to the evenly chocolate brown head of Fox Sparrow (photo above) that only shows a hint of stripes, if any. The lower mandible is bright yellow, in contrast to the dark upper half of the bill. The Fox Sparrow is large with ample square tail, towhee-sized; the Song Sparrow is smaller with rounded tail.

There are other field marks, but the marks just mentioned are easy to remember to get you started.

Song Sparrow ("Rusty" form), Forest Grove, Oregon. 27 November 2008 by Greg Gillson.
For practice in naming the markings of the Song Sparrow's head above, we'll start at the top of the head and work down through the eye to the throat. Here goes. The very center of the crown has a thin gray stripe from the bill over the top of the head. See it? That's the median crown stripe. It goes right over the middle (median) of the crown. Next is a wide brown lateral crown stripe. Lateral is "on the side" and above the broad gray eyebrow stripe. Actually most of the face is gray. There is brown eyestripe through the eye back over the top of the ear coverts. The ear coverts (behind and below the eye) are gray, the lower border of the ear coverts is brown. That's the mustache line and it starts from the gape of the bill ("corner of the mouth"). The submustachial stripe ("below the mustache") is white. There is a broad flaring brown lateral throat stripe.The throat is white. These terms are illustrated in the introduction to most field guides.

Across the continent, despite large variations in darkness or paleness of plumage and overall size, all Song Sparrows have the same basic face pattern.

If you compare with the Fox Sparrow photo above, you'll see that you can't easily see any patterns that you can name. The whole head is rather dark gray brown. The crown (general top of the head) is more dark brown and the sides of the head are more gray. There is some white mixed with brown on the throat, and brown and white unpatterned streaks on the lower face and ear coverts. But, again, nothing that you could name with the clear facial markings terms like in the Song Sparrow.

Both sparrows are found in dense blackberry tangles and brush. The Song Sparrow also likes wetlands and marshes; the Fox Sparrow is more common in clearcuts in the foothills, but there is complete overlap. The Rusty Song Sparrows are resident west of Cascades, though other paler forms may occur in winter. Other, slightly paler and grayer Song Sparrows breed east of the Cascades. The main bulk of wintering Sooty Fox Sparrows in the Pacific Northwest arrive in October and remain until April.

Song Sparrows respond immediately and excitedly to pishing. [For more on pishing, see "The secret to my birding success."] They fly right up to you, out in the open, often responding with their squeaky "chimp" call note. They stay with you as long as you keep pishing. Fox Sparrows, on the other hand, take a bit more coaxing. They take a while to respond. However, if you whistle a pygmy owl imitation or imitate their harsh "check" call note they usually come out into the open to respond with the same call. Again, they tend to stay in the open once they finally respond.

[Footnote: The Thick-billed and Slate-colored Fox Sparrows that summer in the Pacific NW tend to have almost entirely pale gray heads with brown marks on the ear coverts. Their wings and tail are redder than the Sooty Fox Sparrows. They arrive in April and depart in September. Their call notes are a sharp metalic "chink," similar to White-crowned Sparrow or California Towhee. Thick-billed Fox Sparrows like ceanothus and manzanita scrub among regrowing pine seedlings 5-10 years after a clearcut. Slate-colored Fox Sparrows tend to be found in damp mountain seeps and creek bottoms. Song Sparrows east of the Cascades are paler gray and brown, but the head pattern is same as the Song Sparrow described above.]

4 comments:

  1. Good clear descriptions. The one thing I will add is that Sooty Fox Sparrows have a lot of geographic variation in coloration. And a lot of that variation can be seen in the ones wintering or passing through Oregon. They all have pretty much the same pattern as described by Greg, but the actual brown hues very about as much as the hues of chocolate in a fancy candy store. Some are very dark brown, others more reddish brown, Sides of the face vary from dark brown to fairly gray. Back color varies from dark chocolate brown to reddish brown.

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    1. Yes, thanks Wayne. We are talking about 5-7 named subspecies in the Sooty Fox Sparrow group.

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  2. In case anyone wonders, there has been much discussion of splitting Fox Sparrow into 3 or 4 species: Red (Eastern or Taiga), Sooty, Thick-billed, and Slate-colored (or Thick-billed and Slate-colored just one species). The trouble is shown in Sibley's guide, the "Canadian Rocky Mountains form" (altivagans subspecies, I believe) that may be either Red or Slate-colored group.

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  3. Great post and interesting i.d. challenge, especially for newcomers to the wonderful world of birding.

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