Adult swamp sparrow upperparts are dark red-brown, with black streaks and reddish patches on the wings and shoulders. No wing bars. The head is dark gray, with a chestnut crown (brown- and black-streaked, with a gray central stripe). The tail is slightly notched and is usually not pumped up and down in flight like the song sparrow's. Underparts are unstreaked, gray, with a white throat, dark, reddish-brown sides and a dark whisker stripe. Breeding plumage is much more reddish brown, with black streaking on the head and with buffy sides. Young birds resemble the winter plumage but have a buffy eyebrow and nape and fine streaking on the breast. The song is a low, sweet trill, essentially a rapid series of swees or syus, much slower than the notes of a chipping sparrow. Calls are a sharp, metallic tchip and a zeee, similar to those of the Lincoln's sparrow.
- Rusty cap; with gray central stripe in nonbreeding plumage
- No obvious streaking on the gray chest
- Wings reddish brown, with no wing bars
- Throat white
- Gray cheeks and eyebrow
Similar species: Its lack of wing bars separates the swamp sparrow from field sparrows and American tree sparrows. Chipping sparrows have white or whitish eyebrow, not gray; also, they are slimmer and smaller. Lincoln's sparrows, especially immatures, are often confused with swamp sparrows. Note Lincoln's more defined (less diffuse) streaking on breast and flanks.
Length: 5¾ inches (tip of bill to tip of tail).
Habitat and Conservation
Common in swamps, wet meadows, marshes, prairies, hay fields, and weedy fields, where it forages on the ground and in shallow water. It is unlikely that you will see a swamp sparrow at your bird feeder.
Insects and weed, grass, and sedge seeds. Swamp sparrows have relatively long legs, which makes it easier for them to wade into shallow water like a tiny heron in pursuit of small aquatic invertebrates. They sometimes even dip their heads underwater to snatch up aquatic prey.
Common migrant statewide. Uncommon winter resident statewide. Formerly known to breed in certain wetlands in northern Missouri, but not recorded in about a hundred years.
Swamp sparrows are present in Missouri from September through mid-May, when they migrate north to their breeding territory, which stretches through much of Canada and the northern quarter of the United States. Their cup nests are built of dry grasses and other plant materials and lined with finer fibrous matter. Nests are positioned in shrubs, or in bunches of sedges, grasses, or similar plants, or on the ground, in or on the edges of wetlands. A clutch comprises 2–6 eggs. Swamp sparrows can live to be at least 7 years old.
This is one of hundreds of North American birds that will likely be affected by the changing climate within the next 50 to 100 years. Climate conditions favorable for its breeding territory will shift northward out of the United States and into northern Canada. There is wide scientific consensus that climate change is being caused by over a century of our burning of fossil fuels.
Swamp sparrow populations decline when wetland habitats are degraded, polluted, fragmented, or destroyed. Other animals require wetland habitat, too, among them bitterns and other marsh birds, dragonflies, fishes, mammals, and a host of reptile and amphibian species.