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Species · Massachusetts · BBS 2025 Release · 1966–2024

Blue-winged Warbler Population Trend in Massachusetts

All statesForest birds

Blue-winged Warbler in Massachusetts has edged down: down 10% on the route-weighted index since 1969.

-10%Since 1969TrendPercent 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 →
26Routes 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 →
57YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Blue-winged 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 →

No notable trend signals for Blue-winged Warbler in Massachusetts. See the full index history below.

Blue-winged Warbler Population Forecast in Massachusetts

If the recent trend holds, Blue-winged Warbler in Massachusetts is projected to stay roughly flat through 2029, near 0.56 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±37%, with 100% of held-out values landing inside the 95% band.

-6%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 →
0.56Projected 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 →
0.00–1.495% 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 →
±37%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, Blue-winged Warbler in Massachusetts is projected to stay roughly flat through 2029, near 0.56 (95% range 0.00–1.4). A 5-year backtest shows a typical error of ±37%, with 100% of held-out values landing inside the 95% band.19672029
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 →
20250.600.001.4
20260.590.001.4
20270.580.001.4
20280.570.001.4
20290.560.001.4

Blue-winged Warbler Survey Routes in Massachusetts

Routes recording Blue-winged 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 →
S Barre320241969
Prattville220191970
Belchertown220241967
E Dennis119941977
Chilmark119811973
Marion120241969
Ware River120221993
Newburyport120061978
Maynard120001988
Littleton120071975
N Oxford120191974
Mansfield120161971
E Pepperell119891984
Warren120091968
N Orange119991970
Cummington119971973
Chesterfield119961976
Cheshire119911971
Pittsfield120061990
Sheffield120131969
Monterey120242023
Gay Head120212001
Holden120211979
N. Andover120241995
Warren 2120242010

Blue-winged Warbler Population Trend in Other States

alabamaarkansasconnecticutdelawaregeorgiaillinoisindianaiowakentuckymarylandmichiganminnesotamississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandtennesseevermontvirginiawest-virginiawisconsin

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