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Species · California · BBS 2025 Release · 1966–2024

White-faced Ibis Population Trend in California

All statesWetland birds

White-faced Ibis in California has surged: up 24× on the route-weighted index since 1981.

24×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 →
36Routes 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 →
43YearsYears 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 CaliforniaNotable 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 California: up 24× on the route-weighted index since 1981.

White-faced Ibis Population Forecast in California

If the recent trend holds, White-faced Ibis in California is projected to rise about 100% by 2029 — from 4.5 in 2024 to a central estimate of 9.0 (95% range 0.00–20). A 5-year backtest shows a typical error of ±399%, 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 →
9.0Projected 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 →
0.00–2095% 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 →
±399%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 California is projected to rise about 100% by 2029 — from 4.5 in 2024 to a central estimate of 9.0 (95% range 0.00–20). A 5-year backtest shows a typical error of ±399%, with 100% of held-out values landing inside the 95% band.19722029
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 →
20258.50.0020
20268.60.0020
20278.70.0020
20288.80.0020
20299.00.0020

White-faced Ibis Survey Routes in California

Routes recording White-faced Ibis in California.
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 →
Dorris33920191988
Glenn20520211987
Brawley20520121988
Niland18520241981
Arvin15020222012
Likely12220241991
Alamo River12219921992
Palo Verde5820242003
Atwater5020121989
Sattley4920121999
Oroville3520132013
Orland3520042004
Zamora3020172008
Ora Loma3020242024
Red Bluff2920142013
Staten Is.2220141996
Hughson1720242010
Ingalls1720011995
Madeline1520142012
Westley1420231994
Calif City1320122012
Nubieber1220151994
Davis Creek920221990
Buena Vista920191999
Macdoel820191992

White-faced Ibis Population Trend in Other States

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