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

Pied-billed Grebe Population Trend in Idaho

All statesWetland birds

Pied-billed Grebe in Idaho has declined: down 49% on the route-weighted index since 1974.

-49%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 →
16Routes 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 →
44YearsYears 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 IdahoNotable 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 Idaho. See the full index history below.

Pied-billed Grebe Population Forecast in Idaho

If the recent trend holds, Pied-billed Grebe in Idaho is projected to fall about 65% by 2029 — from 0.36 in 2024 to a central estimate of 0.13 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±47.5%, with 100% of held-out values landing inside the 95% band.

-65%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 →
0.13Projected 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 →
0.00–0.4295% 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 →
±47.5%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 Idaho is projected to fall about 65% by 2029 — from 0.36 in 2024 to a central estimate of 0.13 (95% range 0.00–0.42). A 5-year backtest shows a typical error of ±47.5%, with 100% of held-out values landing inside the 95% band.19702029
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 →
20250.130.000.42
20260.130.000.42
20270.130.000.42
20280.130.000.42
20290.130.000.42

Pied-billed Grebe Survey Routes in Idaho

Routes recording Pied-billed Grebe in Idaho.
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 →
Naples920241973
Blackft Res219981996
Cedar Hill220162001
Daniels Res220001997
Cabarton220041990
Triangle220211990
Mivoden120061980
Preston120141990
Dubois119781978
Centerville120082008
Springfield120041970
Magic Mtn120131992
Pasadena Val120141990
Mud Lake119881988
Bates120182001
Dougal Res120212017

Pied-billed Grebe Population Trend in Other States

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

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