BirdAnalyst
Species · Idaho · BBS 2025 Release · 1966–2024

Ruffed Grouse Population Trend in Idaho

All statesGeneralists

Ruffed Grouse in Idaho has declined: down 31% on the route-weighted index since 1978.

-31%Since 1978TrendPercent 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 →
21Routes 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 →
39YearsYears 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 IdahoNotable 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 Ruffed Grouse in Idaho. See the full index history below.

Ruffed Grouse Population Forecast in Idaho

If the recent trend holds, Ruffed Grouse in Idaho is projected to fall about 68% by 2029 — from 0.28 in 2024 to a central estimate of 0.09 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±74.4%, with 80% of held-out values landing inside the 95% band.

-68%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 →
0.09Projected 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 →
0.00–0.2795% 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 →
±74.4%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, Ruffed Grouse in Idaho is projected to fall about 68% by 2029 — from 0.28 in 2024 to a central estimate of 0.09 (95% range 0.00–0.27). A 5-year backtest shows a typical error of ±74.4%, with 80% of held-out values landing inside the 95% band.19722029
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 →
20250.090.000.27
20260.090.000.27
20270.090.000.27
20280.090.000.27
20290.090.000.27

Ruffed Grouse Survey Routes in Idaho

Routes recording Ruffed Grouse in Idaho.
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 →
Cobalt420242013
Leadore220082008
Squirrel220221972
Coolin220241986
Naples120241972
Mivoden120231978
Avery120061996
Lolo Pass120151992
Grangeville120101987
N Fork Cda R120151994
Rochat Divde120221997
Centerville120012001
Magic Mtn120181998
Marble Creek119981992
Joel119901990
Pierce119971997
Burgdorf120112011
Yellow Pine120161989
Featherville120001996
Bates120092006
Nezperce Nf119991999

Ruffed Grouse Population Trend in Other States

alaskaarkansascaliforniaconnecticutgeorgiaindianaiowakentuckymainemarylandmassachusettsmichiganminnesotamontananevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooregonpennsylvaniarhode-islandsouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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