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Species · Massachusetts · BBS 2026 Release · 1966–2025

Yellow Warbler Population Trend in Massachusetts

All statesForest birds

Yellow Warbler in Massachusetts has surged: up 126% on the route-weighted index since 1968.

+126%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 →
32Routes 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 Yellow Warbler Trends in MassachusettsNotable 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 →

Yellow Warbler has surged in Massachusetts: up 126% on the route-weighted index since 1968.

Yellow Warbler Population Forecast in Massachusetts

If the recent trend holds, Yellow Warbler in Massachusetts is projected to fall about 16% by 2030 — from 12 in 2025 to a central estimate of 10 (95% range 7.3–14). A 5-year backtest shows a typical error of ±15.1%, with 80% of held-out values landing inside the 95% band.

-16%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 →
10Projected 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 →
7.3–1495% 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 →
±15.1%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, Yellow Warbler in Massachusetts is projected to fall about 16% by 2030 — from 12 in 2025 to a central estimate of 10 (95% range 7.3–14). A 5-year backtest shows a typical error of ±15.1%, with 80% 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 →
2026107.113
2027107.113
2028107.213
2029107.313
2030107.314

Yellow Warbler Survey Routes in Massachusetts

Routes recording Yellow Warbler in Massachusetts.
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 →
Prattville3220191966
Marion2720251966
Chesterfield2420251967
Belchertown2220251967
Gay Head2220251996
S Barre1920251968
Monterey1920252019
Wellfleet 21920252016
Brockton1420191967
Cheshire1319941969
Warren 21320252010
Wellfleet920071966
E Pepperell919941966
Sheffield820221969
Cummington 2820252015
Hancock720151998
E Dennis620211967
N Orange620251968
Newburyport520221967
Maynard520251967
Princeton519761969
Warren520091968
N Oxford420251968
Cummington420131968
N. Andover420251995

Yellow Warbler Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniacoloradoconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckymainemarylandmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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