BirdAnalyst
Species · New Hampshire · BBS 2026 Release · 1966–2025

Hermit Thrush Population Trend in New Hampshire

All statesForest birds

Hermit Thrush in New Hampshire has risen sharply: up 52% on the route-weighted index since 1968.

+52%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 →
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 →
59YearsYears 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 New HampshireNotable 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 →

Hermit Thrush has risen sharply in New Hampshire: up 52% on the route-weighted index since 1968.

Hermit Thrush Population Forecast in New Hampshire

If the recent trend holds, Hermit Thrush in New Hampshire is projected to rise about 107% by 2030 — from 2.3 in 2025 to a central estimate of 4.9 (95% range 2.3–7.4). A 5-year backtest shows a typical error of ±82.8%, with 60% of held-out values landing inside the 95% band.

+107%Change by 2030TrendPercent 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 →
4.9Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
2.3–7.495% 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 →
±82.8%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 New Hampshire is projected to rise about 107% by 2030 — from 2.3 in 2025 to a central estimate of 4.9 (95% range 2.3–7.4). A 5-year backtest shows a typical error of ±82.8%, with 60% of held-out values landing inside the 95% band.19662030
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 →
20264.72.17.2
20274.72.27.3
20284.82.27.3
20294.82.37.3
20304.92.37.4

Hermit Thrush Survey Routes in New Hampshire

Routes recording Hermit Thrush in New Hampshire.
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 →
Milan1220251967
Dixvil Notch820171966
Glen620251975
Dixville Notch 2620252018
Clarksville520251966
Walpole420251966
Jefferson Hl420251966
Stratford420221966
Concord320241966
Canterbury320251974
Crawford Not319751967
Jeffers Ntch320251993
Peterborough220251967
Epsom220251969
Lempster220251969
Brentwood119981966
Fitzwilliam120241966
Dover120231966
Hopkinton120231966
Strafford120231966
Gilmantn I W120251970
Wilmot120251966
Mt Chocorua120251966
Marlow120251966
Franconia120251966

Hermit Thrush Population Trend in Other States

alaskaarizonacaliforniacoloradoconnecticutidahoindianamainemarylandmassachusettsmichiganminnesotamontananevadanew-jerseynew-mexiconew-yorknorth-carolinaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.