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

Northern Bobwhite Population Trend in Colorado

All statesGrassland birds

Northern Bobwhite in Colorado has fallen sharply: down 75% on the route-weighted index since 1970.

-75%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 →
27Routes 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 →
55YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Northern Bobwhite 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 →

Northern Bobwhite has fallen sharply in Colorado: down 75% on the route-weighted index since 1970.

Northern Bobwhite Population Forecast in Colorado

If the recent trend holds, Northern Bobwhite in Colorado is projected to fall about 100% by 2029 — from 0.15 in 2024 to a central estimate of 0.00 (95% range 0.00–0.80). A 5-year backtest shows a typical error of ±88.9%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–0.8095% 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 →
±88.9%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, Northern Bobwhite in Colorado is projected to fall about 100% by 2029 — from 0.15 in 2024 to a central estimate of 0.00 (95% range 0.00–0.80). A 5-year backtest shows a typical error of ±88.9%, 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 →
20250.010.000.81
20260.000.000.80
20270.000.000.80
20280.000.000.80
20290.000.000.80

Northern Bobwhite Survey Routes in Colorado

Routes recording Northern Bobwhite 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 Bridge1219971992
Fort Morgan520241996
Arsenal319911991
Rush320042004
Neegrande320242023
Edler320241993
Last Chance219741974
Boyero219931990
Doyle Bridge 2220161998
Waverly220191989
Nunn220172017
Julesburg220172004
Pritchett220241999
Stoneham220192001
Pinneo120121976
Fleming120121973
Abarr120191968
Lamar120241973
Two Buttes120091973
Hudson120171989
Gordon Creek120192019
Crowley120171990
Cheyenne120082008
Campo120192016
Burlington120242018

Northern Bobwhite Population Trend in Other States

alabamaarkansasconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourinebraskanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinaohiooklahomaoregonpennsylvaniarhode-islandsouth-carolinasouth-dakotatennesseetexasvermontvirginiawashingtonwest-virginiawisconsinwyoming

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