BirdAnalyst
Species · BCR 10 · BBS 2025 Release · 1966–2024

Western Grebe In Northern Rockies

All regionsNorthern RockiesWetland birds

Western Grebe in Northern Rockies has collapsed: down 82% on the route-weighted index since 1988.

-82%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 →
39Routes 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 Northern Rockies: down 82% on the route-weighted index since 1988.

Western Grebe In Northern Rockies Population Forecast

If the recent trend holds, Western Grebe in Northern Rockies is projected to fall about 100% by 2029 — from 0.16 in 2024 to a central estimate of 0.00 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±166.3%, with 100% of held-out values landing inside the 95% band.

-100%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 →
0.00Projected 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 →
0.00–1.595% 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 →
±166.3%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 Northern Rockies is projected to fall about 100% by 2029 — from 0.16 in 2024 to a central estimate of 0.00 (95% range 0.00–1.5). A 5-year backtest shows a typical error of ±166.3%, 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 →
20250.000.001.5
20260.000.001.5
20270.000.001.5
20280.000.001.5
20290.000.001.5

Routes In Northern Rockies

Routes recording Western Grebe in Northern Rockies.
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 →
Carter 2WYOMING192024
SpartaOREGON122000
MidvaleWYOMING81996
TensleepWYOMING61997
Crane CreekIDAHO42009
Hebgen LakeMONTANA42023
EtheteWYOMING42023
CabartonIDAHO32023
Neponset ResUTAH32018
Rock RiverWYOMING32022
Rawlins 2WYOMING32022
MivodenIDAHO22022
BeaverheadMONTANA22018
Red RockMONTANA21994
RandolphUTAH22005
E. Bear LakeUTAH22006
ClarkWYOMING22001
AlpineWYOMING22022
Mtn ViewWYOMING22024
Flamin GorgeWYOMING22010
NaplesIDAHO11993
Sawtooth CtyIDAHO12014
FeathervilleIDAHO12022
Libby DamMONTANA11986
KalispellMONTANA12003

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