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Species · Maine · BBS 2026 Release · 1966–2025

Blackburnian Warbler Population Trend in Maine

All statesForest birds

Blackburnian Warbler in Maine has surged: up 97% on the route-weighted index since 1968.

+97%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 →
73Routes 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 Blackburnian 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 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 →

Blackburnian Warbler has surged in Maine: up 97% on the route-weighted index since 1968.

Blackburnian Warbler Population Forecast in Maine

If the recent trend holds, Blackburnian Warbler in Maine is projected to fall about 33% by 2030 — from 2.8 in 2025 to a central estimate of 1.9 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±20.6%, with 100% of held-out values landing inside the 95% band.

-33%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 →
1.9Projected 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 →
0.00–4.095% 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 →
±20.6%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, Blackburnian Warbler in Maine is projected to fall about 33% by 2030 — from 2.8 in 2025 to a central estimate of 1.9 (95% range 0.00–4.0). A 5-year backtest shows a typical error of ±20.6%, 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 →
20261.90.004.0
20271.90.004.0
20281.90.004.0
20291.90.004.0
20301.90.004.0

Blackburnian Warbler Survey Routes in Maine

Routes recording Blackburnian 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 →
Northfield3619811976
Waite2819771977
Carrying Pl1220251979
Wilson Mills1020251983
Pillsbury Pd1019681968
Horse Mtn820111983
Wytopitlock620251976
Medway620251976
Forest Sta620001967
Nesowadnehun620211990
Reeds420251994
Manchester419901973
Cooper420211975
Charleston420191977
Topsfield319961978
Eastbrook320251977
Seboomook Lk320141974
Clayton Lake320081977
Boundary320091997
Brownfield320092009
Searsport320162002
Bethel220211979
Greenwood220251982
Hancock220241969
Heron Lake220011983

Blackburnian Warbler Population Trend in Other States

connecticutgeorgiaindianamarylandmassachusettsmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinaohiopennsylvaniarhode-islandtennesseevermontvirginiawest-virginiawisconsin

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