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

Red Crossbill Population Trend in Colorado

All statesGeneralists

Red Crossbill in Colorado has surged: up 161% on the route-weighted index since 1971.

+161%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 →
74Routes 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 →
51YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Red Crossbill 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 →

Red Crossbill has surged in Colorado: up 161% on the route-weighted index since 1971.

Red Crossbill Population Forecast in Colorado

If the recent trend holds, Red Crossbill in Colorado is projected to fall about 27% by 2029 — from 2.9 in 2024 to a central estimate of 2.1 (95% range 0.68–3.5). A 5-year backtest shows a typical error of ±58.4%, 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 →
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 →
0.68–3.595% 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 →
±58.4%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, Red Crossbill in Colorado is projected to fall about 27% by 2029 — from 2.9 in 2024 to a central estimate of 2.1 (95% range 0.68–3.5). A 5-year backtest shows a typical error of ±58.4%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20252.00.563.4
20262.00.593.4
20272.00.623.4
20282.10.653.5
20292.10.683.5

Red Crossbill Survey Routes in Colorado

Routes recording Red Crossbill 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 →
Comanche Pk5920241994
Mcphee Res.4820241997
Haycamp Mesa4720241998
Powderhorn3720182004
Buffalo Park2420231992
Mount Evans2320241996
Pinos Creek2119901988
Rollins Pass2120221998
Stillwater Pass1820072007
Pinon1620241993
Elbert1320241998
Flattops1220141992
Yellowjacket Pass920242024
Kiowa820161969
Summitville820211996
Guffey820241991
Tincup720241992
Cochetopa Pass720072004
Delta620191987
Colona620081984
Castleton620221996
Colona 2620162016
Red Cliff520241989
Como520232013
Deadman Rd.520241992

Red Crossbill Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniageorgiaidahoillinoismainemarylandmassachusettsmichiganminnesotamontananebraskanevadanew-hampshirenew-mexiconew-yorknorth-carolinanorth-dakotaoregonpennsylvaniasouth-carolinasouth-dakotatennesseeutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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