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Species · Colorado · BBS 2025 Release · 1966–2024

Green-tailed Towhee Population Trend in Colorado

All statesGeneralists

Green-tailed Towhee in Colorado has risen sharply: up 69% on the route-weighted index since 1970.

+69%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 →
105Routes 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 →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Green-tailed Towhee 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 →

Green-tailed Towhee has risen sharply in Colorado: up 69% on the route-weighted index since 1970.

Green-tailed Towhee Population Forecast in Colorado

If the recent trend holds, Green-tailed Towhee in Colorado is projected to rise about 16% by 2029 — from 8.2 in 2024 to a central estimate of 9.4 (95% range 6.3–13). A 5-year backtest shows a typical error of ±13.8%, with 100% of held-out values landing inside the 95% band.

+16%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 →
9.4Projected 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 →
6.3–1395% 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 →
±13.8%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, Green-tailed Towhee in Colorado is projected to rise about 16% by 2029 — from 8.2 in 2024 to a central estimate of 9.4 (95% range 6.3–13). A 5-year backtest shows a typical error of ±13.8%, 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 →
20259.26.112
20269.26.112
20279.36.212
20289.46.212
20299.46.313

Green-tailed Towhee Survey Routes in Colorado

Routes recording Green-tailed Towhee 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 →
Yampa9620231969
Mesaverde Np6420241996
Douglas Pass5220241982
Angora4320241998
Uncompahgre4220241988
Powderhorn4020231994
Baxter Pass3920241994
Mcphee Res.3720241996
Black Sulphur Cr3420242015
Wilson Creek3120241990
Yellowjacket Pass2720241998
Paonia2620241992
Dinosaur2620241995
Castleton2420241988
Doyleville2420241988
Thomasville2420181993
Heeney2320192017
Buffalo Park2220231992
Great Divide2120241974
Moon Pass2020241998
Pagosa Spgs1819821968
Deadman Rd.1820241992
Willow Peak1720211988
Stillwater Pass1720091998
Marshall Pas1620191995

Green-tailed Towhee Population Trend in Other States

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