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

Ruffed Grouse Population Trend in New Hampshire

All statesGeneralists

Ruffed Grouse in New Hampshire has collapsed: down 88% on the route-weighted index since 1968.

-88%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 →
24Routes 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 →
47YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Ruffed Grouse 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 declinecomputed 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 →

Ruffed Grouse has collapsed in New Hampshire: down 87% on the route-weighted index since 1968.

Ruffed Grouse Population Forecast in New Hampshire

If the recent trend holds, Ruffed Grouse in New Hampshire is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.19). A 5-year backtest shows a typical error of ±124.9%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.00Projected 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 →
0.00–0.1995% 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 →
±124.9%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, Ruffed Grouse in New Hampshire is projected to stay roughly flat through 2029, near 0.00 (95% range 0.00–0.19). A 5-year backtest shows a typical error of ±124.9%, 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 →
20250.010.000.20
20260.010.000.19
20270.000.000.19
20280.000.000.19
20290.000.000.19

Ruffed Grouse Survey Routes in New Hampshire

Routes recording Ruffed Grouse 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 →
Brentwood319671967
Crawford Not219751966
Peterborough120051968
Fitzwilliam120151968
Dover119751967
Hopkinton120221976
Epsom120191976
Concord120151974
Strafford120151966
Canterbury119901974
Gilmantn I W120011978
Wilmot119991977
Mt Chocorua120191968
Walpole120191968
Marlow120241967
Lempster120161971
Jefferson Hl120122004
Franconia119941966
Milan120031983
Stratford120121966
Dixvil Notch120031971
Clarksville120231966
Glen120231975
Dixville Notch 2120192019

Ruffed Grouse Population Trend in Other States

alaskaarkansascaliforniaconnecticutgeorgiaidahoindianaiowakentuckymainemarylandmassachusettsmichiganminnesotamontananevadanew-jerseynew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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