BirdAnalyst
Species · Maine · BBS 2026 Release · 1966–2025

Pine Warbler Population Trend in Maine

All statesForest birds

Pine Warbler in Maine has surged: up 82× on the route-weighted index since 1973.

82×Since 1973TrendPercent 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 →
58Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Pine 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 →

Pine Warbler has surged in Maine: up 82× on the route-weighted index since 1973.

Pine Warbler Population Forecast in Maine

If the recent trend holds, Pine Warbler in Maine is projected to fall about 30% by 2030 — from 7.4 in 2025 to a central estimate of 5.2 (95% range 3.4–7.0). A 5-year backtest shows a typical error of ±47.9%, with 0% of held-out values landing inside the 95% band.

-30%Change by 2030TrendPercent 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 →
5.2Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
3.4–7.095% 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 →
±47.9%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, Pine Warbler in Maine is projected to fall about 30% by 2030 — from 7.4 in 2025 to a central estimate of 5.2 (95% range 3.4–7.0). A 5-year backtest shows a typical error of ±47.9%, with 0% of held-out values landing inside the 95% band.19712030
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 →
20264.83.06.6
20274.93.16.7
20285.03.26.8
20295.13.36.9
20305.23.47.0

Pine Warbler Survey Routes in Maine

Routes recording Pine 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 →
Carrying Pl1820252002
Brooks1720211986
Turner 21620252011
Turner1420101973
Brownfield 21420252010
Aurora1320211982
Reeds1120251993
Cornville1120252012
Bowdoin Ctr1020211972
Eastbrook1020251977
Westbrook920241979
Greenwood920252014
Hartford920251983
East Troy920191976
Hermon920212009
Medway820251976
Brownfield820092009
Cooper720212005
Carrabassett720251988
Rome720241996
Cape Neddick620241978
Kittery Pt520251986
Newcastle520241978
Charleston520212005
Otisfield Gr420151977

Pine Warbler Population Trend in Other States

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

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.