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Species · Colorado · BBS 2026 Release · 1966–2025

Orange-crowned Warbler Population Trend in Colorado

All statesForest birds

Orange-crowned Warbler in Colorado has surged: up 532% on the route-weighted index since 1973.

+532%Since 1973TrendPercent 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 →
69Routes 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 →
50YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Orange-crowned Warbler 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 increasecomputed 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 →

Orange-crowned Warbler has surged in Colorado: up 532% on the route-weighted index since 1973.

Orange-crowned Warbler Population Forecast in Colorado

If the recent trend holds, Orange-crowned Warbler in Colorado is projected to stay roughly flat through 2030, near 1.3 (95% range 0.83–1.8). A 5-year backtest shows a typical error of ±33.7%, with 80% of held-out values landing inside the 95% band.

-1%Change by 2030TrendPercent 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 →
1.3Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.83–1.895% 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 →
±33.7%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, Orange-crowned Warbler in Colorado is projected to stay roughly flat through 2030, near 1.3 (95% range 0.83–1.8). A 5-year backtest shows a typical error of ±33.7%, with 80% of held-out values landing inside the 95% band.19682030
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 →
20261.20.761.7
20271.30.781.7
20281.30.791.8
20291.30.811.8
20301.30.831.8

Orange-crowned Warbler Survey Routes in Colorado

Routes recording Orange-crowned Warbler 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 →
Owl Creek Pass1620251998
Haycamp Mesa1520251998
Baxter Pass1320241994
Blackhead Pk1320251991
Uncompahgre1220251988
Thomasville1220251997
Wilson Creek820251990
Mcphee Res.820251996
Douglas Pass720241986
Yellowjacket Pass720252007
Yampa620231975
Dolores Riv620251988
Colona 2620252016
Rifle Falls520251999
Delta420211973
Colona420121972
Willow Peak420251988
Dunckley Pas420251994
Fox Creek420252008
Nucla420251999
Aspen320251985
Pagosa Spgs319821974
Lake City320021988
Black Sulphur Cr320252015
Red Cliff220171992

Orange-crowned Warbler Population Trend in Other States

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Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.