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

Osprey Population Trend in Maine

All statesGeneralists

Osprey in Maine has surged: up 80% on the route-weighted index since 1971.

+80%Since 1971TrendPercent 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 →
42Routes 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 →
51YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Osprey 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 →

Osprey has surged in Maine: up 80% on the route-weighted index since 1971.

Osprey Population Forecast in Maine

If the recent trend holds, Osprey in Maine is projected to fall about 28% by 2029 — from 0.32 in 2024 to a central estimate of 0.23 (95% range 0.01–0.44). A 5-year backtest shows a typical error of ±54.3%, with 60% of held-out values landing inside the 95% band.

-28%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 →
0.23Projected 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 →
0.01–0.4495% 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 →
±54.3%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, Osprey in Maine is projected to fall about 28% by 2029 — from 0.32 in 2024 to a central estimate of 0.23 (95% range 0.01–0.44). A 5-year backtest shows a typical error of ±54.3%, with 60% of held-out values landing inside the 95% band.19682029
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 →
20250.220.010.44
20260.220.010.44
20270.230.010.44
20280.230.010.44
20290.230.010.44

Osprey Survey Routes in Maine

Routes recording Osprey 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 →
Cornville420242012
Otisfield Gr320112011
Harmony320232000
Cooper220211977
Deblois220051972
Seboomook Lk219841972
Pillsbury Pd219681968
St David220041983
Cape Neddick119971997
Newcastle120231971
Wilson Mills120211987
Bethel120042004
Greenwood120222005
Hartford120241981
Bowdoin Ctr120111972
Manchester119821982
East Troy120052005
Warren119891973
Heron Lake119981996
Brooks119841984
Eastbrook120231985
Hancock120241970
Castine120061986
Aurora120192019
Moose River119971997

Osprey Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakentuckylouisianamarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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