BirdAnalyst
Species · BBS 2026 Release · 1966–2025

White-faced Ibis Population Analysis

ThreskiornithidaeWetland birdsPlegadis chihi

White-faced Ibis has surged: up 510% on the route-weighted index since 1969.

+510%Since 1969TrendPercent 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 →
265RoutesSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
58Years SurveyedYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

About the White-faced Ibis

The White-faced Ibis (Plegadis chihi) is a North American member of the Ibises & Spoonbills (Threskiornithidae). In this analysis it is grouped with the wetland birds.

Size
21.5–35.5 in long (55–90 cm) — a large wader (typical for the family)
Habitat
Marshes, ponds, lakeshores and other freshwater wetlands.
Diet
Aquatic invertebrates, small fish, frogs and plant matter.
Range
Recorded on 265 Breeding Bird Survey routes across 17 states, most concentrated in the Great Basin.
Family
Threskiornithidae · Wetland birds

Notable White-faced Ibis TrendsNotable 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 surveyed states: up 510% on the route-weighted index since 1969.

White-faced Ibis Population Forecast

If the recent trend holds, White-faced Ibis is projected to rise about 93% by 2030 — from 0.96 in 2025 to a central estimate of 1.9 (95% range 0.83–2.9). A 5-year backtest shows a typical error of ±70.2%, with 80% of held-out values landing inside the 95% band.

+93%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 →
1.9Projected 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 →
0.83–2.995% 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 →
±70.2%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 is projected to rise about 93% by 2030 — from 0.96 in 2025 to a central estimate of 1.9 (95% range 0.83–2.9). A 5-year backtest shows a typical error of ±70.2%, with 80% of held-out values landing inside the 95% band.19672030
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 →
20261.80.732.8
20271.80.762.8
20281.80.782.8
20291.80.812.9
20301.90.832.9

Where the White-faced Ibis Is Detected

BBS routes recording White-faced Ibis, sized by most recent count.

White-faced Ibis Population Trend by State

White-faced Ibis population trend by state.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Arizonainsufficient datan/a2
California31×198136
Colorado-96%199126
Idaho+607%197310
Kansas+217%19763
Louisiana+41%197033
Montanainsufficient datan/a5
Nebraska-1%19909
Nevada23×199215
New Mexicoinsufficient datan/a4
North Dakota+728%200616
Oklahomainsufficient datan/a1
Oregon28×197916
South Dakota-50%20089
Texas-91%196950
Utah14×198123
Wyominginsufficient datan/a7

White-faced Ibis Population Trend by Region

Bird Conservation Regions are the ecological unit for trends.

White-faced Ibis population trend by Bird Conservation Region.
TrendPercent 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 →Baseline yearThe first year of the smoothed window the trend is measured from. An earlier baseline means a longer record stands behind the number.Full methodology →Survey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
Great Basin108×197364
Northern Rockies+28%199211
Prairie Potholes31×200026
Southern Rockies / Colorado Plateau-96%198925
Shortgrass Prairie+0%199525
Central Mixed Grass Prairie-17%197612
Mississippi Alluvial Valley+68%200211
Coastal California19×198618
Sonoran and Mojave Deserts+293%19857
Tamaulipan Brushlands-38%19834
Gulf Coastal Prairie-50%196942

White-faced Ibis Conservation Status

Our route-weighted index shows it up about 510% since 1969.

Source: USGS North American Breeding Bird Survey, retrieved 2026-08-14. Trend is a route-weighted relative-abundance index, not an absolute population.