The Breeding Bird Survey (BBS) is the most reliable source of data for the Swamp Sparrow, although it does not provide good coverage of the northern portion of the population. BBS results show that populations were roughly stable between about 1970 and about 1990, and have shown a steady increase since that time. The Bird Conservation Regions for which reliable trends are available (displayed below) all show positive trends, although of different magnitudes. The Christmas Bird Count (CBC) provides good coverage of this species' wintering grounds, and while it includes birds breeding in the United States, trends are dominated by Canadian birds, which make up over 80% of the continental population. CBC results suggest the continental wintering population shows a negative trend. Between these two sources, the BBS is considered the more reliable survey in part because of its well-standardized design. Thus the Swamp Sparrow is assessed as showing a moderate increase, based on BBS results, but the reliability of that assessment is low due to the conflicting trends and the lack of good coverage of the northern range. The Swamp Sparrow is at an acceptable level relative to its national population goal (see BBS Canada graph below).
Additional information on: Breeding Bird Survey (BBS) - Canadian analysis
Additional information on: Christmas Bird Count (CBC)