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

Yellow-headed Blackbird Population Trend in Colorado

All statesGeneralists

Yellow-headed Blackbird in Colorado has surged: up 353% on the route-weighted index since 1971.

+353%Since 1971TrendPercent 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 →
78Routes 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 Yellow-headed Blackbird 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 →

Yellow-headed Blackbird has surged in Colorado: up 353% on the route-weighted index since 1971.

Yellow-headed Blackbird Population Forecast in Colorado

If the recent trend holds, Yellow-headed Blackbird in Colorado is projected to rise about 99% by 2029 — from 1.1 in 2024 to a central estimate of 2.1 (95% range 0.00–4.2). A 5-year backtest shows a typical error of ±138.9%, with 100% of held-out values landing inside the 95% band.

+99%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 →
2.1Projected 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 →
0.00–4.295% 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 →
±138.9%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, Yellow-headed Blackbird in Colorado is projected to rise about 99% by 2029 — from 1.1 in 2024 to a central estimate of 2.1 (95% range 0.00–4.2). A 5-year backtest shows a typical error of ±138.9%, 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 →
20252.00.004.1
20262.00.004.1
20272.10.004.2
20282.10.004.2
20292.10.004.2

Yellow-headed Blackbird Survey Routes in Colorado

Routes recording Yellow-headed Blackbird 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 →
Alamosa4320241988
Sheridan Lak1920162016
Neegrande1720191999
Timpas1520132003
Arsenal 21320242016
Piceance Basin1020061998
Walden820241990
Last Chance 2820212017
Mcphee Res.720241997
Pagosa Spgs619821982
Lay620241996
Yellowjacket Pass620242001
Doyleville520241988
Gardner520212021
Yampa419821970
Wray Gulch420021989
San Luis420211991
Rio Grnds Rs420031993
Piedra420241993
Flagler420032002
Pritchett420172007
Maybell320241970
Briggsdale319901990
Two Buttes320081985
Castleton320222000

Yellow-headed Blackbird Population Trend in Other States

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