Bird of the Month - Swamp Sparrow
By Andy McCormick
Swamp Sparrow: Melospiza georgiana
Length 5.75”
Wingspan 7.25”
Weight 0.6 oz (17g)
AOU code: SWSP
An apparent spike in reported sightings of Swamp Sparrows in Washington during the fall of 2018 has increased interest in this uncommon wintering sparrow.
RUFOUS WINGS
“If you don’t get lost in the details, this is an easy sparrow to identify: an overall small rufous-onto-dark sparrow plus wetlands equals Swamp” (Dunne, p. 618). However, some details help. The Swamp Sparrow has rufous wings in all plumages. These and its brown body contrast with its mostly gray face and wide gray stripe above the eye. In winter the Swamp Sparrow is more buffy in color with a duller rufous crown separated by a gray stripe (Alderfer). Its chest is gray with little streaking.
The Swamp Sparrow is more closely related to and shares the same genus Melospiza (song finch, from Greek melos, song, and spiza, the chaffinch) with the Song Sparrow (M. melodia). But some wintering Swamp Sparrows can be mistaken for a White-throated Sparrow. However, the Swamp Sparrow is smaller and does not have wing bars (Sibley 2014). It was first collected in the State of Georgia and its species name georgiana honors that state (Holloway).
SWAMP DENIZEN
As its name implies the Swamp Sparrow is found in wetlands characterized by brushy habitat and tall grasses. In winter in Washington it is more likely seen walking in thickets and rank weedy areas along streams or in fields. For much of the year the Swamp Sparrow prefers to eat insects and consumes fewer seeds than any other sparrow (Bell and Kennedy), but in winter it will eat more seeds and will sometimes visit feeders in preferred habitat.
The song is a monotone trill reminiscent of but warmer than the song of a Chipping Sparrow. More likely heard in winter is the call note, a sharp metallic tchip which many compare to that of an Eastern Phoebe (Bell and Kennedy). The song and calls of the Swamp Sparrow can be heard at the Macaulay Library. You can also search for photos at the same site.
WATER IS THE MAJOR CUE FOR BREEDING
Swamp Sparrows which winter in Washington will depart northward beginning in mid-March and be on the breeding grounds by late April. Most breed below the tree line in a variety of wetland habitats ranging from cattail marshes, open cedar forests, and tidal marshes. Shallow standing water is an important foraging habitat for Swamp Sparrows (Mowbray 1997). Swamp Sparrows do not breed in Washington.
The nest consists of a fine cup lined with grasses within a course structure of heavier grass typically built in cattails, sedges, or bushes very close to or above water. The typical 4-5 eggs are pale green to white and heavily marked with brown. The female incubates the eggs and the male feeds her while she is on the nest. The eggs hatch within two weeks and young leave the nest in another week and a half. Swamp Sparrows will often have two broods per year (Kaufman).
CONSERVATION
Swamp Sparrows are still considered abundant and stable in their range in eastern North America. However, some data show fluctuations in populations in the Great Lakes area are possibly due to loss of wetland habitat (Alderfer). Nests built over water offer protection from certain predators, but also subject them to destruction from flooding during the breeding season (Mowbray 1997). Sightings along the west coast are considered rare and dispersed and there is no data regarding why numbers vary year to year.
References available upon request from amccormick@eastsideaudubon.org.
Image of Swamp Sparrow by Tom Murray