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

Great Horned Owl Population Trend in Colorado

All statesGeneralists

Great Horned Owl in Colorado has fallen sharply: down 51% on the route-weighted index since 1970.

-51%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 →
116Routes 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 Great Horned Owl 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 declinecomputed 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 →

Great Horned Owl has fallen sharply in Colorado: down 51% on the route-weighted index since 1970.

Great Horned Owl Population Forecast in Colorado

If the recent trend holds, Great Horned Owl in Colorado is projected to rise about 39% by 2029 — from 0.14 in 2024 to a central estimate of 0.20 (95% range 0.00–0.50). A 5-year backtest shows a typical error of ±57.8%, with 100% of held-out values landing inside the 95% band.

+39%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 →
0.20Projected 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 →
0.00–0.5095% 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 →
±57.8%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, Great Horned Owl in Colorado is projected to rise about 39% by 2029 — from 0.14 in 2024 to a central estimate of 0.20 (95% range 0.00–0.50). A 5-year backtest shows a typical error of ±57.8%, 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 →
20250.210.000.51
20260.210.000.51
20270.210.000.51
20280.200.000.50
20290.200.000.50

Great Horned Owl Survey Routes in Colorado

Routes recording Great Horned Owl 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 →
Doyle Bridge819971992
Briggsdale520241984
Kiowa320181968
Prospect Val320001992
Haswell320111993
Moon Pass320192003
Great Divide220241989
Pinneo220181977
Moffat220141977
Pagosa Spgs219741974
Two Buttes220151984
Castleton220211988
Pinos Creek219901989
Trinchera220211990
Pleasant View220212021
Colona 2220182018
Kirk220231999
Neegrande220191997
Piedra219971997
Mosca220231995
Edler220101992
Flagler220222002
Karval220181995
South Fork220142014
Westcliffe220192003

Great Horned Owl Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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