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

Ruffed Grouse Population Trend in Maryland

All statesGeneralists

Ruffed Grouse in Maryland has declined: down 30% on the route-weighted index since 1981.

-30%Since 1981TrendPercent 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 →
12Routes 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 →
23YearsYears 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 MarylandNotable 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 Maryland. See the full index history below.

Ruffed Grouse Population Forecast in Maryland

If the recent trend holds, Ruffed Grouse in Maryland is projected to stay roughly flat through 2019, near 0.02 (95% range 0.00–0.05). A 5-year backtest shows a typical error of ±37.2%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2019TrendPercent 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 →
0.02Projected 2019 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0595% 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 →
±37.2%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 Maryland is projected to stay roughly flat through 2019, near 0.02 (95% range 0.00–0.05). A 5-year backtest shows a typical error of ±37.2%, with 100% of held-out values landing inside the 95% band.19662019
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 →
20150.020.000.05
20160.020.000.05
20170.020.000.05
20180.020.000.05
20190.020.000.05

Ruffed Grouse Survey Routes in Maryland

Routes recording Ruffed Grouse in Maryland.
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 →
Smithsburg219971997
Finzel220141999
Floyd119861986
Vindex120021966
Oldtown119971979
Potomac Park119991981
Williamsport120132013
Wolfsville119661966
Jennings120122005
Steyer120112011
Green Ridge120021996
Piney Grove120082001

Ruffed Grouse Population Trend in Other States

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

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