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

Alder Flycatcher Population Trend in Maine

All statesAerial insectivores

Alder Flycatcher in Maine has declined: down 37% on the route-weighted index since 1968.

-37%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 →
59YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Alder Flycatcher 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 →

No notable trend signals for Alder Flycatcher in Maine. See the full index history below.

Alder Flycatcher Population Forecast in Maine

If the recent trend holds, Alder Flycatcher in Maine is projected to rise about 28% by 2030 — from 2.8 in 2025 to a central estimate of 3.6 (95% range 1.0–6.3). A 5-year backtest shows a typical error of ±64.4%, with 100% of held-out values landing inside the 95% band.

+28%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 →
3.6Projected 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 →
1.0–6.395% 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 →
±64.4%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, Alder Flycatcher in Maine is projected to rise about 28% by 2030 — from 2.8 in 2025 to a central estimate of 3.6 (95% range 1.0–6.3). A 5-year backtest shows a typical error of ±64.4%, with 100% of held-out values landing inside the 95% band.19662030
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 →
20263.71.16.3
20273.71.16.3
20283.71.06.3
20293.61.06.3
20303.61.06.3

Alder Flycatcher Survey Routes in Maine

Routes recording Alder Flycatcher 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 →
East Troy2120211972
St David2120051982
Harmony1620251974
Benton1519801971
Ludlow1519981968
Ft Fairfield1520051993
Baker Lake1320091995
Hermon1220211966
Deblois1220071966
Cooper1020211975
Northfield1019811976
Washburn1020051979
Warren919901975
Forest Sta920001972
Boundary820161993
Clayton Lake 2820132010
Castine720061976
Clayton Lake720081982
Big Twenty720081993
Weeks Brook720161995
Hancock620251969
Cornville620252012
Carrying Pl520251980
Hudson520161973
Ashland520081980

Alder Flycatcher Population Trend in Other States

alaskaconnecticutidahoillinoisindianaiowamarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooklahomapennsylvaniasouth-dakotavermontvirginiawashingtonwest-virginiawisconsin

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