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

Rock Wren Population Trend in Colorado

All statesForest birds

Rock Wren in Colorado has surged: up 266% on the route-weighted index since 1970.

+266%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 →
116Routes 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 Rock Wren 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 →

Rock Wren has surged in Colorado: up 266% on the route-weighted index since 1970.

Rock Wren Population Forecast in Colorado

If the recent trend holds, Rock Wren in Colorado is projected to rise about 13% by 2030 — from 1.5 in 2025 to a central estimate of 1.7 (95% range 0.91–2.4). A 5-year backtest shows a typical error of ±16.5%, with 100% of held-out values landing inside the 95% band.

+13%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 →
1.7Projected 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 →
0.91–2.495% 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 →
±16.5%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, Rock Wren in Colorado is projected to rise about 13% by 2030 — from 1.5 in 2025 to a central estimate of 1.7 (95% range 0.91–2.4). A 5-year backtest shows a typical error of ±16.5%, 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 →
20261.60.872.4
20271.60.882.4
20281.70.892.4
20291.70.902.4
20301.70.912.4

Rock Wren Survey Routes in Colorado

Routes recording Rock Wren 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 →
Wray Gulch2420251988
Baxter Pass2420241995
Cokedale1720251995
Delta1320211973
Walsenburg1320251994
Powderhorn1120251998
Doyleville920251988
Douglas Pass820241982
Angora820251998
Mesaverde Np820251998
Ludlow620251998
Guffey520251995
Rosevale520252009
Prospect Val519951995
Black Sulphur Cr520252015
Cone Mtn420081988
Browns Park420251992
Lay420251996
Radium419991999
Nucla420251999
Mount Evans420241996
Yampa320231975
Mica Butte319861968
Wilson Creek320251990
Waverly320152004

Rock Wren Population Trend in Other States

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