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

Western Grebe In Great Basin

All regionsGreat BasinWetland birds

Western Grebe in Great Basin has collapsed: down 90% on the route-weighted index since 1988.

-90%Since 1988TrendPercent 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 →
54Routes 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 →
39YearsYears 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 declinecomputed 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 →

Western Grebe has collapsed in Great Basin: down 90% on the route-weighted index since 1988.

Western Grebe In Great Basin Population Forecast

If the recent trend holds, Western Grebe in Great Basin is projected to rise about 113% by 2030 — from 0.54 in 2025 to a central estimate of 1.2 (95% range 0.00–5.2). A 5-year backtest shows a typical error of ±709.5%, with 100% of held-out values landing inside the 95% band.

+113%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 →
1.2Projected 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 →
0.00–5.295% 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 →
±709.5%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, Western Grebe in Great Basin is projected to rise about 113% by 2030 — from 0.54 in 2025 to a central estimate of 1.2 (95% range 0.00–5.2). A 5-year backtest shows a typical error of ±709.5%, with 100% of held-out values landing inside the 95% band.19862030
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 →
20261.50.005.5
20271.40.005.5
20281.30.005.4
20291.20.005.3
20301.20.005.2

Routes In Great Basin

Routes recording Western Grebe 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 →
Iron GateCALIFORNIA1242019
DorrisCALIFORNIA562019
Bear RiverUTAH442025
Modoc PointOREGON332018
Catlow RimOREGON202025
Blacks CreekIDAHO121996
PromontoryUTAH111998
Harney LakeOREGON91995
Hanford SiteWASHINGTON51996
Blizzard GapOREGON42018
Warner VallyOREGON42024
Iron SpringsIDAHO32024
LeamingtonUTAH32014
BentonCALIFORNIA22025
MacdoelCALIFORNIA21998
Clear Lk ResCALIFORNIA22018
MadelineCALIFORNIA22025
Pasadena ValIDAHO22014
Cedar HillIDAHO22016
Alvord LakeOREGON22019
Modoc Point 2OREGON22025
Moses LakeWASHINGTON22016
Horn RapidsWASHINGTON22021
NubieberCALIFORNIA12017
IngallsCALIFORNIA11999

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