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Species · Maine · BBS 2025 Release · 1966–2024

Blackburnian Warbler Population Trend in Maine

All statesForest birds

Blackburnian Warbler in Maine has risen sharply: up 65% on the route-weighted index since 1968.

+65%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 →
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 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 risen sharply in Maine: up 65% 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 rise about 18% by 2029 — from 1.5 in 2024 to a central estimate of 1.8 (95% range 0.00–3.9). A 5-year backtest shows a typical error of ±20.4%, with 100% of held-out values landing inside the 95% band.

+18%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 →
1.8Projected 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 →
0.00–3.995% 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 →
±20.4%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, Blackburnian Warbler in Maine is projected to rise about 18% by 2029 — from 1.5 in 2024 to a central estimate of 1.8 (95% range 0.00–3.9). A 5-year backtest shows a typical error of ±20.4%, 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 →
20251.80.003.9
20261.80.003.9
20271.80.003.9
20281.80.003.9
20291.80.003.9

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
Pillsbury Pd1019681968
Carrying Pl920241979
Horse Mtn820111983
Wilson Mills620241983
Forest Sta620001967
Nesowadnehun620211990
Reeds420241994
Manchester419901973
Eastbrook420241977
Cooper420211975
Charleston420191977
Medway420181976
Topsfield319961978
Seboomook Lk320141974
Clayton Lake320081977
Boundary320091997
Brownfield320092009
Searsport320162002
Bethel220211979
Hartford220171982
Brooks220071979
Hermon220181979
Hancock220241969

Blackburnian Warbler Population Trend in Other States

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

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