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

Ruffed Grouse Population Trend in Pennsylvania

All statesGeneralists

Ruffed Grouse in Pennsylvania has collapsed: down 82% on the route-weighted index since 1968.

-82%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 →
74Routes 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 →
57YearsYears 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 PennsylvaniaNotable 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 Pennsylvania: down 82% on the route-weighted index since 1968.

Ruffed Grouse Population Forecast in Pennsylvania

If the recent trend holds, Ruffed Grouse in Pennsylvania is projected to stay roughly flat through 2028, near 0.03 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±70.5%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.03Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.1495% 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 →
±70.5%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 Pennsylvania is projected to stay roughly flat through 2028, near 0.03 (95% range 0.00–0.14). A 5-year backtest shows a typical error of ±70.5%, with 100% of held-out values landing inside the 95% band.19662028
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 →
20240.040.000.15
20250.040.000.15
20260.040.000.14
20270.040.000.14
20280.030.000.14

Ruffed Grouse Survey Routes in Pennsylvania

Routes recording Ruffed Grouse in Pennsylvania.
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 →
Harmonsburg619771977
Little Marsh420061998
Ralston319661966
Roulette220141974
Austinville219871987
Rector219661966
Clear Spring219821966
Drehersville219891989
Ferris Crnrs120021967
Whig Hill120191970
Ellenton120221986
Teepleville119901967
Sigel120091991
Lynch120211982
N Washington119961968
N Pine Grove119891986
Pottersdale119801980
Odin120041990
Betula120171993
Russell City119941970
Ridgway120072001
Eldred120071973
Rasselas120141988
Starlight 2120172017
Arnot120171987

Ruffed Grouse Population Trend in Other States

alaskaarkansascaliforniaconnecticutgeorgiaidahoindianaiowakentuckymainemarylandmassachusettsmichiganminnesotamontananevadanew-hampshirenew-jerseynew-yorknorth-carolinanorth-dakotaohiooregonrhode-islandsouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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