BirdAnalyst
Species · Utah · BBS 2026 Release · 1966–2025

Western Grebe Population Trend in Utah

All statesWetland birds

Western Grebe in Utah has surged: up 305% on the route-weighted index since 1992.

+305%Since 1992TrendPercent 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 →
23Routes 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 →
35YearsYears 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 UtahNotable 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 increasecomputed 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 surged in Utah: up 305% on the route-weighted index since 1992.

Western Grebe Population Forecast in Utah

If the recent trend holds, Western Grebe in Utah is projected to fall about 37% by 2030 — from 1.7 in 2025 to a central estimate of 1.1 (95% range 0.00–2.2). A 5-year backtest shows a typical error of ±70.5%, with 100% of held-out values landing inside the 95% band.

-37%Change by 2030TrendPercent 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 →
1.1Projected 2030 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–2.295% 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 →
±70.5%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, Western Grebe in Utah is projected to fall about 37% by 2030 — from 1.7 in 2025 to a central estimate of 1.1 (95% range 0.00–2.2). A 5-year backtest shows a typical error of ±70.5%, with 100% of held-out values landing inside the 95% band.19862030
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 →
20261.00.002.1
20271.00.002.1
20281.00.002.2
20291.10.002.2
20301.10.002.2

Western Grebe Survey Routes in Utah

Routes recording Western Grebe in Utah.
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 →
Kamas5420252000
Bear River4420251992
M Warner Res1520251993
Promontory1119981986
Beck519871986
Neponset Res320181995
Leamington320141997
Ferron320252006
E. Bear Lake220062006
Randolph220052002
Monticello220052005
Saleratus Cr120131995
Oak City119861986
Goshen120122000
Navajo Lake120112008
Lynn120231997
Wellington 2120062003
Callao120142004
Dixie Nf120101994
Vernal120101999
Newcastle120092009
Moab119961996
Jensen120022002

Western Grebe Population Trend in Other States

arizonacaliforniacoloradoidahokansasminnesotamontananebraskanevadanew-mexiconorth-dakotaoregonsouth-dakotawashingtonwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14.