BirdAnalyst
Species · New Hampshire · BBS 2025 Release · 1966–2024

Hermit Thrush Population Trend in New Hampshire

All statesForest birds

Hermit Thrush in New Hampshire has risen sharply: up 72% on the route-weighted index since 1968.

+72%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 →
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 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 72% 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 38% by 2029 — from 3.6 in 2024 to a central estimate of 5.0 (95% range 2.5–7.5). A 5-year backtest shows a typical error of ±84.7%, with 60% of held-out values landing inside the 95% band.

+38%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 →
5.0Projected 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 →
2.5–7.595% 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 →
±84.7%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 38% by 2029 — from 3.6 in 2024 to a central estimate of 5.0 (95% range 2.5–7.5). A 5-year backtest shows a typical error of ±84.7%, with 60% 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 →
20254.82.37.3
20264.92.47.3
20274.92.47.4
20285.02.57.4
20295.02.57.5

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 →
Jefferson Hl1220241966
Milan920241967
Dixvil Notch820171966
Glen820241975
Mt Chocorua720241966
Franconia720241966
Clarksville720241966
Dixville Notch 2720242018
Epsom520231969
Wilmot520241966
Canterbury420241974
Marlow420221966
Stratford420221966
Peterborough320241967
Concord320241966
Lempster320191969
Crawford Not319751967
Jeffers Ntch320241993
Gilmantn I W220241970
Walpole220241966
Brentwood119981966
Fitzwilliam120241966
Dover120231966
Hopkinton120231966
Strafford120231966

Hermit Thrush Population Trend in Other States

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

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