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Species · Massachusetts · BBS 2025 Release · 1966–2024

Prairie Warbler Population Trend in Massachusetts

All statesForest birds

Prairie Warbler in Massachusetts has fallen sharply: down 70% on the route-weighted index since 1968.

-70%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 →
27Routes 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 Prairie 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 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 →

Prairie Warbler has fallen sharply in Massachusetts: down 70% on the route-weighted index since 1968.

Prairie Warbler Population Forecast in Massachusetts

If the recent trend holds, Prairie Warbler in Massachusetts is projected to fall about 53% by 2029 — from 1.0 in 2024 to a central estimate of 0.47 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±45%, with 100% of held-out values landing inside the 95% band.

-53%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 →
0.47Projected 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 →
0.00–1.795% 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 →
±45%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, Prairie Warbler in Massachusetts is projected to fall about 53% by 2029 — from 1.0 in 2024 to a central estimate of 0.47 (95% range 0.00–1.7). A 5-year backtest shows a typical error of ±45%, with 100% 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 →
20250.550.001.8
20260.530.001.7
20270.510.001.7
20280.490.001.7
20290.470.001.7

Prairie Warbler Survey Routes in Massachusetts

Routes recording Prairie 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 →
Belchertown620241967
Ware River420221993
Wellfleet 2420242021
Chilmark319831969
Warren220091968
Chesterfield220151984
Cape Cod Ns220071989
Gay Head220241996
Holden220221979
E Dennis120181968
Marion120101966
Wellfleet119981966
Prattville120181967
Brockton120021970
Newburyport119971967
Maynard120111971
Littleton120161967
N Oxford120091968
Mansfield120161969
E Pepperell119891966
S Barre120241968
N Orange120241970
Cummington119971974
Sheffield120021969
N. Andover119951995

Prairie Warbler Population Trend in Other States

alabamaarkansascaliforniaconnecticutdelawarefloridageorgiaillinoisindianakentuckylouisianamainemarylandmichiganmississippimissourinew-hampshirenew-jerseynew-yorknorth-carolinaohiooklahomapennsylvaniarhode-islandsouth-carolinatennesseetexasvermontvirginiawest-virginiawisconsin

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