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

Bay-breasted Warbler Population Trend in Maine

All statesForest birds

Bay-breasted Warbler in Maine has fallen sharply: down 74% on the route-weighted index since 1971.

-74%Since 1971TrendPercent 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 →
57Routes 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 →
52YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bay-breasted 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 →

Bay-breasted Warbler has fallen sharply in Maine: down 74% on the route-weighted index since 1971.

Bay-breasted Warbler Population Forecast in Maine

If the recent trend holds, Bay-breasted Warbler in Maine is projected to stay roughly flat through 2027, near 0.01 (95% range 0.00–0.76). A 5-year backtest shows a typical error of ±44.3%, 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 →
0.01Projected 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 →
0.00–0.7695% 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 →
±44.3%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, Bay-breasted Warbler in Maine is projected to stay roughly flat through 2027, near 0.01 (95% range 0.00–0.76). A 5-year backtest shows a typical error of ±44.3%, with 100% of held-out values landing inside the 95% band.19682027
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 →
20230.080.000.83
20240.070.000.81
20250.050.000.79
20260.030.000.78
20270.010.000.76

Bay-breasted Warbler Survey Routes in Maine

Routes recording Bay-breasted 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 →
Pillsbury Pd819681968
Forest Sta620001969
Northfield519811976
Charleston520161994
Clayton Lake520011977
Nesowadnehun420211990
Hancock420001976
Big Twenty 2320092009
Topsfield319921992
Cooper320211976
Big Twenty320081993
Freedom219761976
Eastbrook219721972
Baxter219841979
Winn219981978
Waite219771977
St David220041982
Telos220061995
Baker Lake220011995
Yankeetuladi220091995
Northfield 2120131992
Biddeford119851976
Andover120172010
Wilson Mills120211983
Bethel120091988

Bay-breasted Warbler Population Trend in Other States

michiganminnesotanew-hampshirenew-yorkpennsylvaniavermontwisconsin

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