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Species · Massachusetts · BBS 2025 Release · 1966–2024

Winter Wren Population Trend in Massachusetts

All statesForest birds

Winter Wren in Massachusetts has surged: up 283% on the route-weighted index since 1969.

+283%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 →
20Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Winter Wren 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 →

Winter Wren has surged in Massachusetts: up 283% on the route-weighted index since 1969.

Winter Wren Population Forecast in Massachusetts

If the recent trend holds, Winter Wren in Massachusetts is projected to stay roughly flat through 2029, near 0.81 (95% range 0.32–1.3). A 5-year backtest shows a typical error of ±15.4%, with 100% of held-out values landing inside the 95% band.

+1%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 →
0.81Projected 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 →
0.32–1.395% 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 →
±15.4%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, Winter Wren in Massachusetts is projected to stay roughly flat through 2029, near 0.81 (95% range 0.32–1.3). A 5-year backtest shows a typical error of ±15.4%, 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 →
20250.770.281.2
20260.780.291.3
20270.790.301.3
20280.800.311.3
20290.810.321.3

Winter Wren Survey Routes in Massachusetts

Routes recording Winter Wren 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 →
Cummington 2520242015
Hancock420132001
Ware River220211993
N Orange220241968
Cummington220141968
Monterey220242019
Prattville120052005
Cape Cod Ns119921992
Newburyport119881988
Maynard119731973
Littleton120001992
Mansfield119991999
Belchertown120241993
Warren119901990
S Barre120141991
Chesterfield120241968
Pittsfield120091967
Sheffield120221975
Holden120241980
N. Andover120052005

Winter Wren Population Trend in Other States

connecticutmainemarylandmichiganminnesotanew-hampshirenew-jerseynew-yorknorth-carolinaohiopennsylvaniatennesseevermontvirginiawest-virginiawisconsin

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