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Species · Massachusetts · BBS 2025 Release · 1966–2024

Hermit Thrush Population Trend in Massachusetts

All statesForest birds

Hermit Thrush in Massachusetts has increased: up 33% on the route-weighted index since 1968.

+33%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 →
30Routes 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 Hermit Thrush 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 Hermit Thrush in Massachusetts. See the full index history below.

Hermit Thrush Population Forecast in Massachusetts

If the recent trend holds, Hermit Thrush in Massachusetts is projected to rise about 84% by 2029 — from 1.1 in 2024 to a central estimate of 2.0 (95% range 0.81–3.1). A 5-year backtest shows a typical error of ±70.9%, with 100% of held-out values landing inside the 95% band.

+84%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 →
2.0Projected 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 →
0.81–3.195% 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 →
±70.9%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, Hermit Thrush in Massachusetts is projected to rise about 84% by 2029 — from 1.1 in 2024 to a central estimate of 2.0 (95% range 0.81–3.1). A 5-year backtest shows a typical error of ±70.9%, 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 →
20251.90.753.1
20261.90.773.1
20271.90.783.1
20281.90.803.1
20292.00.813.1

Hermit Thrush Survey Routes in Massachusetts

Routes recording Hermit Thrush 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 →
Ware River1420221993
Cummington520141968
Chesterfield520241967
Pittsfield520161967
Maynard420061967
Wellfleet 2420242016
Princeton319761970
N Orange320241968
Marion219941966
Wellfleet219981966
Warren220011968
Sheffield220221969
Cummington 2220242015
Hancock220151997
E Dennis119861967
Prattville120141966
Brockton119751975
Newburyport120091967
Littleton120071973
N Oxford120221995
Mansfield119871987
E Pepperell119881970
Belchertown120241967
S Barre120161976
Cheshire119921969

Hermit Thrush Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutidahomainemarylandmichiganminnesotamontananevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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