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

Western Grebe Population Trend in Idaho

All statesWetland birds

Western Grebe in Idaho has collapsed: down 91% on the route-weighted index since 1988.

-91%Since 1988TrendPercent 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 →
15Routes 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 →
38YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Western 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 →

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 →

Western Grebe has collapsed in Idaho: down 91% on the route-weighted index since 1988.

Western Grebe Population Forecast in Idaho

If the recent trend holds, Western Grebe in Idaho is projected to fall about 100% by 2029 — from 0.12 in 2024 to a central estimate of 0.00 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±338.9%, 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 →
0.00–3.095% 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 →
±338.9%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, Western Grebe in Idaho is projected to fall about 100% by 2029 — from 0.12 in 2024 to a central estimate of 0.00 (95% range 0.00–3.0). A 5-year backtest shows a typical error of ±338.9%, with 100% of held-out values landing inside the 95% band.19862029
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 →
20250.000.003.0
20260.000.003.0
20270.000.003.0
20280.000.003.0
20290.000.003.0

Western Grebe Survey Routes in Idaho

Routes recording Western 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 →
Blacks Creek1219961996
Crane Creek420091995
Cabarton320231986
Iron Springs320241998
Mivoden220222022
Cedar Hill220162014
Pasadena Val220141987
Naples119931993
Daniels Res120161988
Preston120231990
Kyle Canyon119961996
Sawtooth Cty120141988
Springfield120151986
Triangle120081988
Featherville120221989

Western Grebe Population Trend in Other States

arizonacaliforniacoloradokansasminnesotamontananebraskanevadanew-mexiconorth-dakotaoregonsouth-dakotautahwashingtonwyoming

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