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

Prairie Warbler Population Trend in Maine

All statesForest birds

Prairie Warbler in Maine has surged: up 196% on the route-weighted index since 1978.

+196%Since 1978TrendPercent 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 →
16Routes 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 →
47YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Prairie Warbler 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 →

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Prairie Warbler has surged in Maine: up 196% on the route-weighted index since 1978.

Prairie Warbler Population Forecast in Maine

If the recent trend holds, Prairie Warbler in Maine is projected to fall about 22% by 2029 — from 0.26 in 2024 to a central estimate of 0.20 (95% range 0.03–0.38). A 5-year backtest shows a typical error of ±55.4%, with 100% of held-out values landing inside the 95% band.

-22%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 →
0.20Projected 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 →
0.03–0.3895% 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 →
±55.4%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, Prairie Warbler in Maine is projected to fall about 22% by 2029 — from 0.26 in 2024 to a central estimate of 0.20 (95% range 0.03–0.38). A 5-year backtest shows a typical error of ±55.4%, with 100% of held-out values landing inside the 95% band.19722029
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 →
20250.190.010.37
20260.200.020.37
20270.200.020.38
20280.200.020.38
20290.200.030.38

Prairie Warbler Survey Routes in Maine

Routes recording Prairie Warbler 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 →
Biddeford320191977
Turner220101987
Otisfield Gr219981998
East Troy220192016
Turner 2220242024
Westbrook120241977
Newcastle119791979
Greenwood120232016
Hartford120242019
Bowdoin Ctr120211991
Manchester119811978
Benton119721972
Brooks120192017
Searsport120192019
Hancock120122012
Brownfield 2120242021

Prairie Warbler Population Trend in Other States

alabamaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianakentuckylouisianamarylandmassachusettsmichiganmississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsin

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