25 March 2021
Nest only in wetlands. In the northern parts of the range, they use fens and bogs that have patches of open water, especially those dotted with shrubs. They also nest in peat bogs with little open water. Through most of the breeding range, look for them in freshwater marshes with cattail, sedges, and other tall reeds, rushes, or grasses; these areas often have willows or alders around their edges. In the mid-Atlantic states, “Coastal Plain” Swamp Sparrows (the nigrescens subspecies) nest in brackish marshes in tidal rivers, mostly in the higher portion of the marshes where salt-meadow hay is dotted with small shrubs like marsh elder and groundsel. During migration, large numbers of Swamp Sparrows mix with Song, Lincoln’s, and White-throated Sparrows in the East, especially in coastal locations prone to “fallouts” of migrants. In such cases, the birds might be a considerable distance from the nearest wetland.