BirdAnalyst
Species · Colorado · BBS 2025 Release · 1966–2024

Ash-throated Flycatcher Population Trend in Colorado

All statesAerial insectivores

Ash-throated Flycatcher in Colorado has surged: up 839% on the route-weighted index since 1972.

+839%Since 1972TrendPercent 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 →
61Routes 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 Ash-throated Flycatcher 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 →

Ash-throated Flycatcher has surged in Colorado: up 839% on the route-weighted index since 1972.

Ash-throated Flycatcher Population Forecast in Colorado

If the recent trend holds, Ash-throated Flycatcher in Colorado is projected to fall about 11% by 2029 — from 1.9 in 2024 to a central estimate of 1.7 (95% range 1.2–2.2). A 5-year backtest shows a typical error of ±21.1%, with 100% of held-out values landing inside the 95% band.

-11%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 →
1.7Projected 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 →
1.2–2.295% 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 →
±21.1%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, Ash-throated Flycatcher in Colorado is projected to fall about 11% by 2029 — from 1.9 in 2024 to a central estimate of 1.7 (95% range 1.2–2.2). A 5-year backtest shows a typical error of ±21.1%, 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 →
20251.61.12.1
20261.61.12.1
20271.61.12.1
20281.71.22.1
20291.71.22.2

Ash-throated Flycatcher Survey Routes in Colorado

Routes recording Ash-throated Flycatcher 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 →
Baxter Pass2320241995
Cokedale2320241995
Douglas Pass2120241982
Walsenburg2020241995
Angora1320241998
Wray Gulch1220231988
Nucla1120241999
Animas1020041996
De Beque1020241992
Ludlow1020162001
Rosevale920242009
Browns Park820241992
Delta720211973
Falfa620241971
Animas 2620212005
Pinon620242007
Trinchera520222005
Paonia520241993
Rifle Falls520211998
Maybell420241992
Basin420241996
Mesaverde Np320241996
Wilson Creek320241992
Doyle Bridge 2320232001
Timpas320131995

Ash-throated Flycatcher Population Trend in Other States

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