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Species · Colorado · BBS 2025 Release · 1966–2024

Pied-billed Grebe Population Trend in Colorado

All statesWetland birds

Pied-billed Grebe in Colorado has declined: down 27% on the route-weighted index since 1974.

-27%Since 1974TrendPercent 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 →
35Routes 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 →
42YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Pied-billed Grebe 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 Pied-billed Grebe in Colorado. See the full index history below.

Pied-billed Grebe Population Forecast in Colorado

If the recent trend holds, Pied-billed Grebe in Colorado is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±138.1%, with 100% of held-out values landing inside the 95% band.

n/aChange 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 →
0.07Projected 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 →
0.00–0.1795% 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 →
±138.1%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, Pied-billed Grebe in Colorado is projected to stay roughly flat through 2029, near 0.07 (95% range 0.00–0.17). A 5-year backtest shows a typical error of ±138.1%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.070.000.17
20260.070.000.17
20270.070.000.17
20280.070.000.17
20290.070.000.17

Pied-billed Grebe Survey Routes in Colorado

Routes recording Pied-billed Grebe 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 →
Cortez1020081990
Great Divide320162014
Arsenal319991991
Kiowa320161973
Last Chance220161988
Lamar219981997
Rio Grnds Rs220162002
Walden220221996
Hudson219891989
Cortez 2220172009
Steamboat L.220022002
Baxter Pass220162006
Browns Park220052003
Douglas Pass120222016
Arsenal 2120162016
Dolores119851969
Falfa119971997
Pagosa Spgs119761976
Dinosaur120171998
Lay120002000
Doyleville120061996
Nunn120182016
Fort Morgan120102009
Julesburg120131998
Alamosa120241994

Pied-billed Grebe Population Trend in Other States

alabamaalaskaarizonaarkansascaliforniaconnecticutdelawarefloridageorgiaidahoillinoisindianaiowakansaskentuckylouisianamainemarylandmassachusettsmichiganminnesotamississippimissourimontananebraskanevadanew-hampshirenew-jerseynew-mexiconew-yorknorth-carolinanorth-dakotaohiooklahomaoregonpennsylvaniasouth-carolinasouth-dakotatennesseetexasutahvermontvirginiawashingtonwisconsinwyoming

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