Swamp Sparrow

A fairly uncommon sparrow normally present in Sonoma County only in the winter months, and only sporadically. Earliest arrivals are usually reported in the first part of October. Most have left by the end of February. Perhaps most common from late October to late December--although never truly common here. Sightings anywhere in the county cause a modest stir in the local birding community. Usually reported only a few times each year and not at all some years. Mainly a bird of the central and eastern United States and Canada. Breeds from the Great Lakes north. Winters south into central Mexico. Usually solitary, but occasionally forms small flocks. Sometimes mixes with other sparrows. A skulker. Likes to stay hidden low in plants in marshy areas or along pond edges.

Swamp Sparrow is a fairly small, dark sparrow that is often hard to get a good look at because of its habit of hiding in vegetation. Often a glimpse is enough to identify this bird, however. In particular, look for the grey face, upper breast, and nape, and the very richly rufous back, wings, and tail. The back and wings are variably striped with black. In breeding plumage, Swamp Sparrow has a rufous crown as well, but we see these birds in their non-breeding colors, when the cap is usually a duller brown, streaked, and with a central grey stripe. Small bill is often yellowish at the base. Whitish at the throat, with white set off by fine black stripes. Flanks variably washed with rufous. Fine, indistinct streaking usually present as well. Face pattern is variable. The ear patch may be quite dark as in the bird pictured above or may be considerably washed out, leaving the face looking mostly grey. A dark line extending from behind the eye ending in a narrow triangle of color is usually evident, however. Area just below the ear patch may be quite grey (as above) but sometimes tends toward a distinctly beige color. Juveniles look like winter adults but with more prominent streaking on flanks and upper breast.

Most likely to be confused with its close relatives in the genus Melospiza--Song Sparrow (Melospiza melodia) and Lincoln’s Sparrow (Melospiza lincolnii). Lincoln’s Sparrow is similarly shy and, like Swamp Sparrow, is present in Sonoma County mainly during the winter months, but Lincoln’s Sparrow has fine (yet quite obvious), crisp, dashed black striping on the upper breast and flanks. The breast and flanks are washed with buff, and, although the belly is a clean white in Lincoln’s Sparrow, the overall impression the bird gives is often of a buff or beige color tinted with grey. Lincoln’s Sparrow has a distinctive head shape (slightly pointed or crested, photo below) that, once learned, is often enough to identify that bird at a glance. Song Sparrow is much the most common of the three birds and present in the county year-round. Song Sparrow is highly variable, but typical Sonoma County birds will be marked with brown, grey, and black with little suggestion of the rich rufous of Swamp Sparrow (or the beige tones of Lincoln’s Sparrow). Note Song Sparrow’s much coarser, messy striping often coalescing at the upper breast into a distinct spot (photos below). Both Lincoln’s and Swamp Sparrow may have a suggestion of such a spot, but the spot is usually very distinct in Song Sparrow, paler and indistinct (though quite clearly present) in Lincoln’s Sparrow, and only vaguely suggested in Swamp Sparrow--if present at all. The Sibley guide to Western birds shows these three species on two adjoining pages for easy comparison. Savannah Sparrow (Passerculus sandwichensis) is another common sparrow in the county with similar markings worth reviewing.

Swamp Sparrow may also suggest Chipping Sparrow (Spizella passerina) in non-breeding plumage, but that bird has a grey rather than rufous rump and has a prominent pale eyebrow lacking in Swamp Sparrow. Also, Chipping Sparrow lacks rufous on the flanks, which is typical in Swamp Sparrow. More important, perhaps, Chipping Sparrow is a bird of open woods as likely as not to be perched in a tree, whereas Swamp Sparrow frequents heavily vegetated freshwater edge habitats and always seems to be ducking for cover in low brush.

Selected county sightings: Laguna de Santa Rosa (11/22, 2012, Scott Carey); Place to Play Park (11/15/-11/18, 2012, Colin Talcroft); Spring Lake (10/17, 2012, Tom McCuller); Willow Creek Rd. (2/14, 2012, Dan Nelson); Ragle Ranch Regional Park (10/24, 2011), Spring Lake (2/8, 2011, Ruth Rudesill); Laguna De Santa Rosa (1/5, 2011, Scott Carey); Ellis Creek Water Treatment Facility (12/27, 2010, Ruth Rudesill); Ellis Creek Water Treatment Facility (12/27 2012, Colin Talcroft)