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

Alder Flycatcher Population Trend in Maine

All statesAerial insectivores

Alder Flycatcher in Maine has declined: down 45% on the route-weighted index since 1968.

-45%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 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 54% by 2029 — from 2.4 in 2024 to a central estimate of 3.7 (95% range 1.0–6.3). A 5-year backtest shows a typical error of ±79.4%, with 100% of held-out values landing inside the 95% band.

+54%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 →
3.7Projected 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 →
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 →
±79.4%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 54% by 2029 — from 2.4 in 2024 to a central estimate of 3.7 (95% range 1.0–6.3). A 5-year backtest shows a typical error of ±79.4%, 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 →
20253.71.16.3
20263.71.06.3
20273.71.06.3
20283.71.06.3
20293.71.06.3

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 →
St David2120051982
Harmony1720241974
Benton1519801971
Ludlow1519981968
Ft Fairfield1520051993
Baker Lake1320091995
Deblois1220071966
Cooper1020211975
Northfield1019811976
Washburn1020051979
Warren919901975
Forest Sta920001972
Hancock820241969
Boundary820161993
Clayton Lake 2820132010
Castine720061976
Clayton Lake720081982
Big Twenty720081993
Weeks Brook720161995
East Troy620191972
Hermon520191966
Hudson520161973
Ashland520081980
Heron Lake520031983
Greenwood420212005

Alder Flycatcher Population Trend in Other States

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

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