BirdAnalyst
Species · BBS 2025 Release · 1966–2024

Swamp Sparrow

PasserellidaeWetland birdsMelospiza georgiana

Swamp Sparrow has held roughly steady: up 9% on the route-weighted index since 1968.

+9%Since 1968TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
798RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the Swamp Sparrow

The Swamp Sparrow (Melospiza georgiana) is a North American member of the New World Sparrows (Passerellidae). In this analysis it is grouped with the wetland birds.

Size
4.5–7.5 in long (12–19 cm) — a small songbird (typical for the family)
Habitat
Marshes, ponds, lakeshores and other freshwater wetlands.
Diet
Aquatic invertebrates, small fish, frogs and plant matter.
Range
Recorded on 798 Breeding Bird Survey routes across 23 states, most concentrated in the Atlantic Northern Forest.
Family
Passerellidae · Wetland birds

Notable Swamp Sparrow TrendsNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Swamp Sparrow. See the full index history below.

Swamp Sparrow Population Forecast

If the recent trend holds, Swamp Sparrow is projected to fall about 10% by 2029 — from 0.42 in 2024 to a central estimate of 0.38 (95% range 0.32–0.45). A 5-year backtest shows a typical error of ±9.5%, with 80% of held-out values landing inside the 95% band.

-10%Change by 2029TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
0.38Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.32–0.4595% range95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
±9.5%Backtest errorBacktest errorTypical error when we hold out the most recent years, forecast them, and compare to what actually happened. Lower means a more trustworthy projection.Full methodology →
If the recent trend holds, Swamp Sparrow is projected to fall about 10% by 2029 — from 0.42 in 2024 to a central estimate of 0.38 (95% range 0.32–0.45). A 5-year backtest shows a typical error of ±9.5%, with 80% of held-out values landing inside the 95% band.19662029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →95% low95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →95% high95% rangeThe 95% uncertainty band around the projection at the forecast horizon. The true value should land inside it most of the time.Full methodology →
20250.380.310.44
20260.380.310.44
20270.380.310.44
20280.380.310.44
20290.380.320.45

Where the Swamp Sparrow Is Detected

BBS routes recording Swamp Sparrow, sized by most recent count.

Swamp Sparrow Population Trend by State

Swamp Sparrow population trend by state.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Connecticut+21%196920
Delaware+7%196812
Illinois-39%197421
Indiana-72%197517
Iowa-59%197414
Maine+48%196867
Maryland+40%196916
Massachusetts+87%196824
Michigan+449%196892
Minnesota+191%196985
Nebraska+124%19803
New Hampshire-19%196826
New Jersey-80%196816
New York+125%1968120
North Dakota+708%197420
Ohio+65%196833
Pennsylvania+57%196871
Rhode Island-40%19705
South Dakota+110%197110
Vermont+28%196824
Virginiainsufficient datan/a4
West Virginiainsufficient datan/a6
Wisconsin+37%196892

Swamp Sparrow Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

Swamp Sparrow population trend by Bird Conservation Region.
TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Prairie Potholes13×197062
Boreal Hardwood Transition+364%1968119
Lower Great Lakes / St. Lawrence Plain+94%196880
Atlantic Northern Forest+9%1968141
Eastern Tallgrass Prairie-15%196847
Prairie Hardwood Transition+59%1968133
Appalachian Mountains+92%1968130
Piedmont-59%19786
New England / Mid-Atlantic Coast+3%196876

Swamp Sparrow Conservation Status

Our route-weighted index shows it up about 8% since 1968.

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22. Trend is a route-weighted relative-abundance index, not an absolute population.