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

Western Grebe In Great Basin

All regionsGreat BasinWetland birds

Western Grebe in Great Basin has collapsed: down 92% on the route-weighted index since 1988.

-92%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 →
53Routes 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 →
38YearsYears 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 92% 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 755% by 2029 — from 0.16 in 2024 to a central estimate of 1.3 (95% range 0.00–5.5). A 5-year backtest shows a typical error of ±871.5%, with 100% of held-out values landing inside the 95% band.

+755%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 →
1.3Projected 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 →
0.00–5.595% 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 →
±871.5%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 755% by 2029 — from 0.16 in 2024 to a central estimate of 1.3 (95% range 0.00–5.5). A 5-year backtest shows a typical error of ±871.5%, with 100% of held-out values landing inside the 95% band.19862029
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 →
20251.60.005.8
20261.60.005.7
20271.50.005.6
20281.40.005.5
20291.30.005.5

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
Modoc PointOREGON332018
Bear RiverUTAH222023
Blacks CreekIDAHO121996
PromontoryUTAH111998
Harney LakeOREGON91995
Fish LakeOREGON62024
Catlow RimOREGON52024
Hanford SiteWASHINGTON51996
Blizzard GapOREGON42018
Warner VallyOREGON42024
MadelineCALIFORNIA32017
Iron SpringsIDAHO32024
Modoc Point 2OREGON32024
LeamingtonUTAH32014
MacdoelCALIFORNIA21998
Clear Lk ResCALIFORNIA22018
Pasadena ValIDAHO22014
Cedar HillIDAHO22016
Alvord LakeOREGON22019
Moses LakeWASHINGTON22016
Horn RapidsWASHINGTON22021
NubieberCALIFORNIA12017
IngallsCALIFORNIA11999

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