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

Greater Sage-Grouse Population Trend in Colorado

All statesGeneralists

Greater Sage-Grouse in Colorado has collapsed: down 84% on the route-weighted index since 1975.

-84%Since 1975TrendPercent 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 →
10Routes 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 →
38YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Greater Sage-Grouse Trends in ColoradoNotable 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 →

Greater Sage-Grouse has collapsed in Colorado: down 84% on the route-weighted index since 1975.

Greater Sage-Grouse Population Forecast in Colorado

If the recent trend holds, Greater Sage-Grouse in Colorado is projected to fall about 100% by 2027 — from 0.05 in 2022 to a central estimate of 0.00 (95% range 0.00–0.60). A 5-year backtest shows a typical error of ±76.8%, with 100% of held-out values landing inside the 95% band.

-100%Change by 2027TrendPercent 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 2027 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.6095% 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 →
±76.8%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, Greater Sage-Grouse in Colorado is projected to fall about 100% by 2027 — from 0.05 in 2022 to a central estimate of 0.00 (95% range 0.00–0.60). A 5-year backtest shows a typical error of ±76.8%, with 100% of held-out values landing inside the 95% band.19722027
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 →
20230.020.000.62
20240.020.000.62
20250.010.000.61
20260.000.000.60
20270.000.000.60

Greater Sage-Grouse Survey Routes in Colorado

Routes recording Greater Sage-Grouse in Colorado.
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 →
Yellowjacket Pass520182018
Black Sulphur Cr520222017
Lay320142000
Walden220171995
Wilson Creek120162016
Maybell120171972
Great Divide120181976
Browns Park119921992
Buffalo Park120132013
Dinosaur120161998

Greater Sage-Grouse Population Trend in Other States

californiaidahomontananevadanorth-dakotaoregonsouth-dakotautahwyoming

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