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

Bald Eagle Population Trend in Maine

All statesGeneralists

Bald Eagle in Maine has surged: up 575% on the route-weighted index since 1997.

+575%Since 1997TrendPercent 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 →
23Routes 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 →
25YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bald Eagle 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 →

Bald Eagle has surged in Maine: up 575% on the route-weighted index since 1997.

Bald Eagle Population Forecast in Maine

If the recent trend holds, Bald Eagle in Maine is projected to rise about 35% by 2029 — from 0.10 in 2024 to a central estimate of 0.14 (95% range 0.01–0.27). A 5-year backtest shows a typical error of ±56.6%, with 20% of held-out values landing inside the 95% band.

+35%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 →
0.14Projected 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 →
0.01–0.2795% 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 →
±56.6%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, Bald Eagle in Maine is projected to rise about 35% by 2029 — from 0.10 in 2024 to a central estimate of 0.14 (95% range 0.01–0.27). A 5-year backtest shows a typical error of ±56.6%, with 20% of held-out values landing inside the 95% band.19802029
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 →
20250.130.000.26
20260.130.000.26
20270.140.010.26
20280.140.010.27
20290.140.010.27

Bald Eagle Survey Routes in Maine

Routes recording Bald Eagle 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 →
Kittery Pt220232019
Greenwood220012001
Turner 2220242024
Wilson Mills120232008
Hartford120171997
Harmony120132013
Hermon120052005
Brownfield 2120232023
Cooper120211980
Carrying Pl120192019
Carrabassett120232018
Charleston120072007
Seboomook Lk120052005
Medway120181998
Clayton Lake119991999
Lake Moxie120132012
Ashland120062006
Cornville120232021
Searsport120222022
Baker Lake120002000
Rome120122012
Jefferson119961996
Church Hill120142014

Bald Eagle Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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