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Species · Maine · BBS 2025 Release · 1966–2024

Black-and-white Warbler Population Trend in Maine

All statesForest birds

Black-and-white Warbler in Maine has surged: up 111% on the route-weighted index since 1968.

+111%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 →
77Routes 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 Black-and-white 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 →

Black-and-white Warbler has surged in Maine: up 111% on the route-weighted index since 1968.

Black-and-white Warbler Population Forecast in Maine

If the recent trend holds, Black-and-white Warbler in Maine is projected to rise about 23% by 2029 — from 4.2 in 2024 to a central estimate of 5.1 (95% range 0.79–9.4). A 5-year backtest shows a typical error of ±22.4%, with 100% of held-out values landing inside the 95% band.

+23%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 →
5.1Projected 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 →
0.79–9.495% 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 →
±22.4%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, Black-and-white Warbler in Maine is projected to rise about 23% by 2029 — from 4.2 in 2024 to a central estimate of 5.1 (95% range 0.79–9.4). A 5-year backtest shows a typical error of ±22.4%, with 100% 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 →
20255.10.769.4
20265.10.779.4
20275.10.789.4
20285.10.789.4
20295.10.799.4

Black-and-white Warbler Survey Routes in Maine

Routes recording Black-and-white 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 →
Northfield4819811976
Cooper1720211975
East Troy1620191973
Brooks1620191977
Charleston1620191975
Medway1620181976
Hudson1620161973
Harmony1520241967
Hermon1520191966
Seboomook Lk1320141972
Topsfield1219961978
Aurora1120211975
Waite1119771977
Searsport1120242002
Forest Sta1020001966
Stacyville920242021
Bowdoin Ctr820211972
Manchester819951971
Winn820221969
Eastbrook720241971
Grnd Lk Strm720001966
Reeds620241990
Warren619901973
Horse Mtn620111983
Andover620212010

Black-and-white Warbler Population Trend in Other States

alabamaarkansascaliforniaconnecticutdelawaregeorgiaillinoisindianakansaskentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsinwyoming

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