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

Nashville Warbler Population Trend in Maine

All statesForest birds

Nashville Warbler in Maine has fallen sharply: down 54% on the route-weighted index since 1968.

-54%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 →
76Routes 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 Nashville 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 →

Nashville Warbler has fallen sharply in Maine: down 54% on the route-weighted index since 1968.

Nashville Warbler Population Forecast in Maine

If the recent trend holds, Nashville Warbler in Maine is projected to rise about 29% by 2030 — from 2.0 in 2025 to a central estimate of 2.6 (95% range 0.00–7.5). A 5-year backtest shows a typical error of ±193.2%, with 100% of held-out values landing inside the 95% band.

+29%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 →
2.6Projected 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 →
0.00–7.595% 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 →
±193.2%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, Nashville Warbler in Maine is projected to rise about 29% by 2030 — from 2.0 in 2025 to a central estimate of 2.6 (95% range 0.00–7.5). A 5-year backtest shows a typical error of ±193.2%, 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 →
20262.80.007.7
20272.70.007.7
20282.70.007.6
20292.60.007.6
20302.60.007.5

Nashville Warbler Survey Routes in Maine

Routes recording Nashville 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 →
Northfield7719811976
Pillsbury Pd2219681968
Big Twenty 22220092009
Heron Lake1920031983
Big Twenty1820081993
Forest Sta1620001966
Topsfield1519961978
Telos1320041995
Waite1119771977
Seboomook Lk1020141978
Grnd Lk Strm1020001966
Nesowadnehun1020211990
Ashland920081980
Yankeetuladi920091994
Warren819901973
Weeks Brook820161995
Baker Lake820091994
Deblois720071966
Wilson Mills620251983
Reeds620251990
Cooper620211975
Charleston620191977
Winn620251969
Hudson620091974
Ludlow619981968

Nashville Warbler Population Trend in Other States

californiaconnecticutidahomarylandmassachusettsmichiganminnesotamontananew-hampshirenew-jerseynew-yorknorth-dakotaoregonpennsylvaniarhode-islandvermontvirginiawashingtonwest-virginiawisconsin

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