BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

White-faced Ibis In Great Basin

All regionsGreat BasinWetland birds

White-faced Ibis in Great Basin has surged: up 77× on the route-weighted index since 1973.

77×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 →
61Routes 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 →
50YearsYears 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 77× 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 128% by 2029 — from 8.9 in 2024 to a central estimate of 20 (95% range 4.9–36). A 5-year backtest shows a typical error of ±133.6%, with 80% of held-out values landing inside the 95% band.

+128%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 →
20Projected 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 →
4.9–3695% 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 →
±133.6%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 128% by 2029 — from 8.9 in 2024 to a central estimate of 20 (95% range 4.9–36). A 5-year backtest shows a typical error of ±133.6%, with 80% of held-out values landing inside the 95% band.19712029
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 →
2025193.835
2026194.035
2027204.335
2028204.635
2029204.936

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 →
Bear RiverUTAH27882023
PromontoryUTAH3552024
DorrisCALIFORNIA3392019
Ruby Valley 2NEVADA3252024
Warner VallyOREGON2942024
FallonNEVADA1312023
LikelyCALIFORNIA1222024
HikoNEVADA1052021
Fish LakeOREGON1022024
MerrillOREGON502022
FairfieldUTAH461988
PrestonIDAHO372023
Catlow RimOREGON342024
Cedar HillIDAHO292022
PocatelloIDAHO252019
SheavilleOREGON252022
CortezNEVADA242022
Carson RiverNEVADA242002
Ruby ValleyNEVADA202001
Harney LakeOREGON182006
IngallsCALIFORNIA172001
Chimney Res.NEVADA162017
Oak CityUTAH162016
MadelineCALIFORNIA152014
NubieberCALIFORNIA122015

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