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Species · Massachusetts · BBS 2025 Release · 1966–2024

Yellow Warbler Population Trend in Massachusetts

All statesForest birds

Yellow Warbler in Massachusetts has surged: up 108% on the route-weighted index since 1968.

+108%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 →
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 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 108% 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 21% by 2029 — from 13 in 2024 to a central estimate of 10 (95% range 7.1–13). A 5-year backtest shows a typical error of ±16.9%, with 80% of held-out values landing inside the 95% band.

-21%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 →
10Projected 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 →
7.1–1395% 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 →
±16.9%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 21% by 2029 — from 13 in 2024 to a central estimate of 10 (95% range 7.1–13). A 5-year backtest shows a typical error of ±16.9%, with 80% 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 →
20259.96.913
202610.06.913
2027107.013
2028107.013
2029107.113

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 →
Chesterfield3320241967
Prattville3220191966
Marion3120241966
S Barre1920241968
Wellfleet 21720242016
Brockton1420191967
Belchertown1420241967
Monterey1420242019
N Orange1320241968
Cheshire1319941969
Gay Head1320241996
N. Andover1120241995
Warren 21020242010
Wellfleet920071966
E Pepperell919941966
Sheffield820221969
Holden720241977
Hancock720151998
E Dennis620211967
Cummington 2620242015
Newburyport520221967
Mansfield520241974
Princeton519761969
Warren520091968
Cummington420131968

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 2026-05-22.