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

Wilson's Warbler Population Trend in Maine

All statesForest birds

Wilson's Warbler in Maine has collapsed: down 84% on the route-weighted index since 1969.

-84%Since 1969TrendPercent 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 →
43Routes 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 →
46YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Wilson's 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 declinecomputed 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 →

Wilson's Warbler has collapsed in Maine: down 84% on the route-weighted index since 1969.

Wilson's Warbler Population Forecast in Maine

If the recent trend holds, Wilson's Warbler in Maine is projected to stay roughly flat through 2027, near 0.04 (95% range 0.00–0.19). A 5-year backtest shows a typical error of ±107.4%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2027TrendPercent 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 →
0.04Projected 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1995% 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 →
±107.4%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, Wilson's Warbler in Maine is projected to stay roughly flat through 2027, near 0.04 (95% range 0.00–0.19). A 5-year backtest shows a typical error of ±107.4%, with 100% of held-out values landing inside the 95% band.19672027
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 →
20230.060.000.20
20240.050.000.20
20250.050.000.19
20260.050.000.19
20270.040.000.19

Wilson's Warbler Survey Routes in Maine

Routes recording Wilson's 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 →
Ludlow319831979
Nesowadnehun220091990
Topsfield219921992
Heron Lake220031984
Aurora220041996
Northfield219811978
Hudson219881982
Forest Sta220001967
Pillsbury Pd219681968
Ft Fairfield219931993
Northfield 2120221998
Wilson Mills119931986
Bethel119891989
Reeds119991996
South Arm119981993
Otisfield Gr120011976
Hartford119771977
Manchester119811981
Warren119741974
Freedom119741974
Clayton Lake 2120102010
Hermon119841984
Hancock120001978
Cooper120062004
Deblois119841968

Wilson's Warbler Population Trend in Other States

alaskacaliforniacoloradoidahomichiganminnesotamontananevadanew-hampshirenew-mexiconew-yorkoregonutahvermontwashingtonwisconsinwyoming

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