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Species · Massachusetts · BBS 2025 Release · 1966–2024

Pine Warbler Population Trend in Massachusetts

All statesForest birds

Pine Warbler in Massachusetts has surged: up 499% on the route-weighted index since 1968.

+499%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 →
28Routes 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 Pine 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 →

Pine Warbler has surged in Massachusetts: up 499% on the route-weighted index since 1968.

Pine Warbler Population Forecast in Massachusetts

If the recent trend holds, Pine Warbler in Massachusetts is projected to rise about 14% by 2029 — from 10 in 2024 to a central estimate of 12 (95% range 8.1–16). A 5-year backtest shows a typical error of ±11.1%, with 100% of held-out values landing inside the 95% band.

+14%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 →
12Projected 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 →
8.1–1695% 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 →
±11.1%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, Pine Warbler in Massachusetts is projected to rise about 14% by 2029 — from 10 in 2024 to a central estimate of 12 (95% range 8.1–16). A 5-year backtest shows a typical error of ±11.1%, 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 →
2025117.315
2026117.515
2027117.715
2028127.915
2029128.116

Pine Warbler Survey Routes in Massachusetts

Routes recording Pine 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 →
Wellfleet 24020242016
Marion2820241970
Cape Cod Ns2420071989
Ware River2320221993
Prattville1720191966
Maynard1720221988
Holden1720241978
S Barre1320241983
N Orange1320241980
Belchertown820241977
Chesterfield720242002
Monterey720242019
Gay Head720241996
N. Andover720241995
Brockton620191990
Wellfleet520071966
Warren520091976
Chilmark419831971
Newburyport420221993
Littleton420241978
Mansfield320241990
Sheffield320222005
N Oxford220222004
Warren 2220242010
E Dennis120211967

Pine Warbler Population Trend in Other States

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

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