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

Osprey Population Trend in Colorado

All statesGeneralists

Osprey in Colorado has surged: up 247% on the route-weighted index since 1998.

+247%Since 1998TrendPercent 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 →
22Routes 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 →
28YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Osprey 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 →

Osprey has surged in Colorado: up 246% on the route-weighted index since 1998.

Osprey Population Forecast in Colorado

If the recent trend holds, Osprey in Colorado is projected to fall about 11% by 2029 — from 0.07 in 2024 to a central estimate of 0.06 (95% range 0.04–0.09). A 5-year backtest shows a typical error of ±15.3%, 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 →
0.06Projected 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 →
0.04–0.0995% 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 →
±15.3%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, Osprey in Colorado is projected to fall about 11% by 2029 — from 0.07 in 2024 to a central estimate of 0.06 (95% range 0.04–0.09). A 5-year backtest shows a typical error of ±15.3%, with 100% of held-out values landing inside the 95% band.19882029
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 →
20250.060.030.09
20260.060.030.09
20270.060.030.09
20280.060.040.09
20290.060.040.09

Osprey Survey Routes in Colorado

Routes recording Osprey 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 →
Aspen320242017
Lake City 2220242016
Harmony120232023
Arsenal120072007
Last Chance120092009
Rio Grnds Rs120161994
Lost Lake120192000
Cortez 2120142014
Tarryall120192019
Steamboat L.120142014
Gold Hill 2120242019
De Beque120242003
Thomasville120172013
Haswell120112011
Neegrande120031998
Groundhog Rs120212021
Angora120222008
Piedra120152001
Gold Hill120061999
Rifle Falls120172017
Rollins Pass120212007
Cortez119881988

Osprey Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwest-virginiawisconsinwyoming

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