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Species · Colorado · BBS 2025 Release · 1966–2024

Bewick's Wren Population Trend in Colorado

All statesForest birds

Bewick's Wren in Colorado has surged: up 92% on the route-weighted index since 1973.

+92%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 →
57Routes 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 →
53YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bewick's 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 →

Bewick's Wren has surged in Colorado: up 92% on the route-weighted index since 1973.

Bewick's Wren Population Forecast in Colorado

If the recent trend holds, Bewick's Wren in Colorado is projected to rise about 27% by 2029 — from 0.48 in 2024 to a central estimate of 0.61 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±53.4%, with 100% of held-out values landing inside the 95% band.

+27%Change by 2029TrendPercent 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 →
0.61Projected 2029 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–1.595% 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 →
±53.4%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, Bewick's Wren in Colorado is projected to rise about 27% by 2029 — from 0.48 in 2024 to a central estimate of 0.61 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±53.4%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.610.001.5
20260.610.001.5
20270.610.001.5
20280.610.001.5
20290.610.001.5

Bewick's Wren Survey Routes in Colorado

Routes recording Bewick's 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 →
Moffat4619871981
Animas1120001996
Delta820211973
Blackhead Pk820192019
Maybell620241973
Walsenburg620242019
Rosevale520242009
Angora520241998
Dolores419791968
Lay420241997
Browns Park420241992
Harmony319761973
Rifle Falls320171999
Gardner320071998
Mesaverde Np220241996
Mica Butte219781975
Wray Gulch220231988
Animas 2220182017
Dolores Riv219881988
Piedra219931992
Cokedale220241995
Nucla220221999
Owl Creek Pass220012001
Haycamp Mesa220042002
Black Sulphur Cr220242023

Bewick's Wren Population Trend in Other States

alabamaarizonaarkansascaliforniaidahoillinoisindianaiowakansaskentuckymarylandmississippimissourinevadanew-mexiconorth-carolinaohiooklahomaoregonpennsylvaniatennesseetexasutahvirginiawashingtonwest-virginiawisconsinwyoming

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