BirdAnalyst
Species · Colorado · BBS 2026 Release · 1966–2025

Warbling Vireo Population Trend in Colorado

All statesForest birds

Warbling Vireo in Colorado has surged: up 353% on the route-weighted index since 1970.

+353%Since 1970TrendPercent 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 →
111Routes 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 Warbling Vireo 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 →

Warbling Vireo has surged in Colorado: up 353% on the route-weighted index since 1970.

Warbling Vireo Population Forecast in Colorado

If the recent trend holds, Warbling Vireo in Colorado is projected to stay roughly flat through 2030, near 12 (95% range 8.8–15). A 5-year backtest shows a typical error of ±7.4%, with 100% of held-out values landing inside the 95% band.

+7%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 →
12Projected 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 →
8.8–1595% 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 →
±7.4%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, Warbling Vireo in Colorado is projected to stay roughly flat through 2030, near 12 (95% range 8.8–15). A 5-year backtest shows a typical error of ±7.4%, with 100% 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 →
2026118.315
2027128.415
2028128.615
2029128.715
2030128.815

Warbling Vireo Survey Routes in Colorado

Routes recording Warbling Vireo 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 →
Dolores Riv8420251988
Dunckley Pas5920251992
Mcphee Res.4620251996
Owl Creek Pass4420251998
Flattops4120251992
Haycamp Mesa4020251998
Blackhead Pk3820251991
Groundhog Rs3320251992
Fox Creek3220251993
Baxter Pass3220241994
Aspen3120251979
Parlin3120251968
Uncompahgre3120251988
Colona 23120252015
Lake City 23120252016
Stillwater Pass3120091999
Rifle Falls3020251998
Guanella Pas2720251992
Willow Peak2620251988
Thomasville2620251992
Moon Pass2520251998
Marshall Pas2420191995
Lost Lake2320251990
Castleton2320251988
Comanche Pk2320241994

Warbling Vireo Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniaconnecticutdelawareidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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