BirdAnalyst
Species · Colorado · BBS 2026 Release · 1966–2025

Red Crossbill Population Trend in Colorado

All statesForest birds

Red Crossbill in Colorado has surged: up 135% on the route-weighted index since 1971.

+135%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 →
52YearsYears 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 135% 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 rise about 135% by 2030 — from 0.86 in 2025 to a central estimate of 2.0 (95% range 0.60–3.4). A 5-year backtest shows a typical error of ±86.1%, with 100% of held-out values landing inside the 95% band.

+135%Change by 2030TrendPercent 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 →
2.0Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.60–3.495% 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 →
±86.1%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, Red Crossbill in Colorado is projected to rise about 135% by 2030 — from 0.86 in 2025 to a central estimate of 2.0 (95% range 0.60–3.4). A 5-year backtest shows a typical error of ±86.1%, with 100% of held-out values landing inside the 95% band.19692030
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 →
20261.90.493.3
20271.90.523.4
20282.00.553.4
20292.00.573.4
20302.00.603.4

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
Powderhorn3720182004
Mount Evans2320241996
Pinos Creek2119901988
Stillwater Pass1820072007
Tincup1620251992
Elbert1320241998
Blackhead Pk1120251996
Buffalo Park1020251992
Deadman Rd.1020251992
Yellowjacket Pass920242024
Haycamp Mesa920251998
Kiowa820161969
Summitville820211996
Guffey820241991
Flattops720251992
Cochetopa Pass720072004
Delta620191987
Colona620081984
Castleton620221996
Colona 2620162016
Red Cliff520241989
Guanella Pas520251995
Nucla520242004

Red Crossbill Population Trend in Other States

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

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.