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

American Wigeon Population Trend in Colorado

All statesWaterfowl

American Wigeon in Colorado has held roughly steady: down 5% on the route-weighted index since 1979.

-5%Since 1979TrendPercent 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 →
37YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable American Wigeon 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 →

No notable trend signals for American Wigeon in Colorado. See the full index history below.

American Wigeon Population Forecast in Colorado

If the recent trend holds, American Wigeon in Colorado is projected to stay roughly flat through 2028, near 0.18 (95% range 0.00–0.56). A 5-year backtest shows a typical error of ±508.2%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.18Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.5695% 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 →
±508.2%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, American Wigeon in Colorado is projected to stay roughly flat through 2028, near 0.18 (95% range 0.00–0.56). A 5-year backtest shows a typical error of ±508.2%, with 100% of held-out values landing inside the 95% band.19732028
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 →
20240.180.000.57
20250.180.000.56
20260.180.000.56
20270.180.000.56
20280.180.000.56

American Wigeon Survey Routes in Colorado

Routes recording American Wigeon 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 →
Walden520151990
Julesburg420122002
Grover420082008
Haswell419961996
Cortez420062000
Wildhorse L319991999
Arsenal 2220222022
Kiowa220122004
Last Chance220052005
Dinosaur220211995
Guffey220182016
Nunn220172017
Alamosa220081988
Mcphee Res.220041997
Amherst220091998
Piedra220141992
Yellowjacket Pass220232013
Cochetopa Pass220152015
Great Divide120221979
Pinneo119731973
Moffat119761976
Lamar120232023
Rio Grnds Rs120221991
Lay120221996
Tincup120181994

American Wigeon Population Trend in Other States

alaskacaliforniaidahokansasmichiganminnesotamontananebraskanevadanew-mexiconorth-dakotaohiooregonpennsylvaniasouth-dakotatexasutahwashingtonwisconsinwyoming

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