BirdAnalyst
Species · Maine · BBS 2025 Release · 1966–2024

Swamp Sparrow Population Trend in Maine

All statesGeneralists

Swamp Sparrow in Maine has increased: up 48% on the route-weighted index since 1968.

+48%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 →
67Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Swamp Sparrow Trends in MaineNotable 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 in Maine. See the full index history below.

Swamp Sparrow Population Forecast in Maine

If the recent trend holds, Swamp Sparrow in Maine is projected to fall about 26% by 2029 — from 1.2 in 2024 to a central estimate of 0.89 (95% range 0.42–1.4). A 5-year backtest shows a typical error of ±24.7%, with 80% of held-out values landing inside the 95% band.

-26%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 →
0.89Projected 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 →
0.42–1.495% 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 →
±24.7%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 in Maine is projected to fall about 26% by 2029 — from 1.2 in 2024 to a central estimate of 0.89 (95% range 0.42–1.4). A 5-year backtest shows a typical error of ±24.7%, 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 →
20250.890.421.4
20260.890.421.4
20270.890.421.4
20280.890.421.4
20290.890.421.4

Swamp Sparrow Survey Routes in Maine

Routes recording Swamp Sparrow in Maine.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Northfield819811976
Carrying Pl720241980
Forest Sta620001970
Waite519771977
Turner420021972
Greenwood420241974
Benton419711971
Grnd Lk Strm420001966
Cape Neddick319731972
Bethel320191977
Reeds320241992
Hermon320171966
Charleston320191977
Medway320181976
Pillsbury Pd319681968
Washburn320051995
Northfield 2320221992
Jefferson320101991
Westbrook220241977
Wilson Mills220231983
East Troy220181972
Andover220212010
Moose River220081983
Carrabassett220241983
Clayton Lake220001977

Swamp Sparrow Population Trend in Other States

connecticutdelawareillinoisindianaiowamarylandmassachusettsmichiganminnesotanebraskanew-hampshirenew-jerseynew-yorknorth-dakotaohiopennsylvaniarhode-islandsouth-dakotavermontvirginiawest-virginiawisconsin

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.