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

Virginia's Warbler Population Trend in Colorado

All statesForest birds

Virginia's Warbler in Colorado has surged: up 356% on the route-weighted index since 1973.

+356%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 →
65Routes 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 →
54YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Virginia's 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 →

Virginia's Warbler has surged in Colorado: up 356% on the route-weighted index since 1973.

Virginia's Warbler Population Forecast in Colorado

If the recent trend holds, Virginia's Warbler in Colorado is projected to stay roughly flat through 2030, near 1.6 (95% range 0.95–2.3). A 5-year backtest shows a typical error of ±37%, with 60% of held-out values landing inside the 95% band.

+2%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 →
1.6Projected 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 →
0.95–2.395% 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%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, Virginia's Warbler in Colorado is projected to stay roughly flat through 2030, near 1.6 (95% range 0.95–2.3). A 5-year backtest shows a typical error of ±37%, with 60% of held-out values landing inside the 95% band.19692030
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 →
20261.60.882.2
20271.60.902.3
20281.60.922.3
20291.60.942.3
20301.60.952.3

Virginia's Warbler Survey Routes in Colorado

Routes recording Virginia's 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 →
Mesaverde Np3920251996
Baxter Pass3520241996
Douglas Pass2420241982
Blackhead Pk2120251993
Gribbles Prk1220251998
Cokedale1120251995
Wet Mtns.1020251993
Yellowjacket Pass1020251998
Wilson Creek920251990
Buford820251980
Ragged Mtn.820191994
Delta720211973
Rifle Falls720251998
Rosevale620232009
Cortez 2520172009
Willow Peak520251996
Dolores Riv520251988
Marshall Pas520021998
Nucla520251999
Aspen420251980
Pagosa Spgs419751975
Thomasville420251998
Gold Hill420121998
Haycamp Mesa420241998
Powderhorn320252022

Virginia's Warbler Population Trend in Other States

arizonacaliforniaidahonevadanew-mexicosouth-dakotautahwyoming

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