BirdAnalyst
Species · BCR 16 · BBS 2026 Release · 1966–2025

Western Grebe In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauWetland birds

Western Grebe in Southern Rockies / Colorado Plateau has surged: up 232% on the route-weighted index since 1990.

+232%Since 1990TrendPercent 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 →
29Routes 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 →
37YearsYears 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 →

Western Grebe has surged in Southern Rockies / Colorado Plateau: up 231% on the route-weighted index since 1990.

Western Grebe In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Western Grebe in Southern Rockies / Colorado Plateau is projected to fall about 19% by 2030 — from 0.57 in 2025 to a central estimate of 0.46 (95% range 0.20–0.73). A 5-year backtest shows a typical error of ±38.2%, with 100% of held-out values landing inside the 95% band.

-19%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 →
0.46Projected 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 →
0.20–0.7395% 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 →
±38.2%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, Western Grebe in Southern Rockies / Colorado Plateau is projected to fall about 19% by 2030 — from 0.57 in 2025 to a central estimate of 0.46 (95% range 0.20–0.73). A 5-year backtest shows a typical error of ±38.2%, 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 →
20260.420.160.69
20270.430.170.70
20280.440.180.71
20290.450.190.72
20300.460.200.73

Routes In Southern Rockies / Colorado Plateau

Routes recording Western Grebe in Southern Rockies / Colorado Plateau.
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 →
KamasUTAH542025
M Warner ResUTAH152025
DulceNEW-MEXICO62025
Cortez 2COLORADO52017
BeckUTAH51987
GuffeyCOLORADO42025
BrookhurstWYOMING42015
Groundhog RsCOLORADO32025
Stillwater PassCOLORADO32006
FerronUTAH32025
WaldenCOLORADO22016
AlamosaCOLORADO22014
San LuisCOLORADO22024
MonticelloUTAH22005
HarmonyCOLORADO12007
FalfaCOLORADO12014
TarryallCOLORADO12018
CortezCOLORADO12008
ThomasvilleCOLORADO12006
DinosaurCOLORADO12016
Gold HillCOLORADO12001
Rifle FallsCOLORADO12014
Stinking Lk.NEW-MEXICO11992
Navajo LakeUTAH12011
JensenUTAH12002

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