Occurrence in Amherst & Connecticut Valley, Mass.
C19

Regular summer resident

April - October

C20

Common transient, and summer resident in suitable swamps, occasionally wintering

March - November

C21

Widespread migrant, especially abundant in October

April - November

Habitat
Fresh marshes with tussocks, bushes, or cattails, sedgy swamps
Nest Materials
coarse and fine grasses, marsh plants, dead cattail blades, leaves
19th-20th Century Field Notes
SWAMP SPARROW . Crown , bright bay , blackening in front ; above , thickly streaked with black and bay ; beneath , clear ash . Length , 5 3 - 4 inches . More common than usually supposed , but very shy , and only to be found in thick swamps . Earliest arrival , April 29th ; departs in October . Although its nest has not yet been found here , it w doubtedly breeds , as I have seen the birds all through the summer , around Adams ' Pond . Feeds on seeds and insects . Not injurious . Note , a loud chirp .

—H.L. Clark, 1887

21st Century Conservation Notes

Undoubtedly has declined with loss of marsh habitat, but still widespread and common. Localized salt-marsh race on Atlantic Coast could be vulnerable to habitat loss.*