BirdAnalyst
Species · BCR 9 · BBS 2026 Release · 1966–2025

White-faced Ibis In Great Basin

All regionsGreat BasinWetland birds

White-faced Ibis in Great Basin has surged: up 108× on the route-weighted index since 1973.

108×Since 1973TrendPercent 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 →
64Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
51YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 Great Basin: up 108× on the route-weighted index since 1973.

White-faced Ibis In Great Basin Population Forecast

If the recent trend holds, White-faced Ibis in Great Basin is projected to rise about 59% by 2030 — from 13 in 2025 to a central estimate of 21 (95% range 5.8–36). A 5-year backtest shows a typical error of ±72.1%, with 100% of held-out values landing inside the 95% band.

+59%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 →
21Projected 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 →
5.8–3695% 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 →
±72.1%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 Great Basin is projected to rise about 59% by 2030 — from 13 in 2025 to a central estimate of 21 (95% range 5.8–36). A 5-year backtest shows a typical error of ±72.1%, with 100% of held-out values landing inside the 95% band.19712030
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 →
2026204.635
2027204.935
2028205.235
2029215.536
2030215.836

Routes In Great Basin

Routes recording White-faced Ibis in Great Basin.
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 →
Mud LakeIDAHO5562025
Bear RiverUTAH5032025
DorrisCALIFORNIA3392019
Ruby Valley 2NEVADA3252024
Warner VallyOREGON2942024
Catlow RimOREGON2622025
Fish LakeOREGON1662025
HikoNEVADA1052021
LikelyCALIFORNIA782025
Blizzard GapOREGON592025
CedarvilleCALIFORNIA552025
MerrillOREGON502022
FairfieldUTAH461988
PrestonIDAHO372023
Cedar HillIDAHO292022
PocatelloIDAHO252019
SheavilleOREGON252022
CortezNEVADA242022
Carson RiverNEVADA242002
Ruby ValleyNEVADA202001
Harney LakeOREGON182006
IngallsCALIFORNIA172001
Chimney Res.NEVADA162017
Oak CityUTAH162016
MadelineCALIFORNIA152014

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