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Species · Utah · BBS 2025 Release · 1966–2024

White-faced Ibis Population Trend in Utah

All statesWetland birds

White-faced Ibis in Utah has surged: up 910% on the route-weighted index since 1981.

+910%Since 1981TrendPercent 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 →
41YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable White-faced Ibis 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 →

White-faced Ibis has surged in Utah: up 910% on the route-weighted index since 1981.

White-faced Ibis Population Forecast in Utah

If the recent trend holds, White-faced Ibis in Utah is projected to rise about 85% by 2029 — from 6.0 in 2024 to a central estimate of 11 (95% range 0.00–26). A 5-year backtest shows a typical error of ±983%, with 60% of held-out values landing inside the 95% band.

+85%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 →
11Projected 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 →
0.00–2695% 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 →
±983%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, White-faced Ibis in Utah is projected to rise about 85% by 2029 — from 6.0 in 2024 to a central estimate of 11 (95% range 0.00–26). A 5-year backtest shows a typical error of ±983%, with 60% of held-out values landing inside the 95% band.19732029
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 →
2025110.0026
2026110.0026
2027110.0026
2028110.0026
2029110.0026

White-faced Ibis Survey Routes in Utah

Routes recording White-faced Ibis 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 →
Bear River278820231992
Promontory35520241973
Fairfield4619881988
Neponset Res3720181997
Oak City1620161981
Randolph1220221992
Delta1020101987
Crawford Mts720172017
Lynn720212000
Escalante619991999
Grantsville520192019
Gold Hill420212013
Wellington 2320112010
Wellington 3120232014
Timpie Spg119901983
Goshen120231987
Aneth120032003
Callao120241992
Dixie Nf120132013
Snowville120152015
Wellington120011997
Pine Creek119971997
Alton120002000

White-faced Ibis Population Trend in Other States

arizonacaliforniacoloradoidahokansaslouisianamontananebraskanevadanew-mexiconorth-dakotaoklahomaoregonsouth-dakotatexaswyoming

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