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

Pied-billed Grebe In Great Basin

All regionsGreat BasinWetland birds

Pied-billed Grebe in Great Basin has risen sharply: up 54% on the route-weighted index since 1970.

+54%Since 1970TrendPercent 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 →
89Routes 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 →
57YearsYears 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 →

Pied-billed Grebe has risen sharply in Great Basin: up 54% on the route-weighted index since 1970.

Pied-billed Grebe In Great Basin Population Forecast

If the recent trend holds, Pied-billed Grebe in Great Basin is projected to rise about 30% by 2030 — from 0.19 in 2025 to a central estimate of 0.25 (95% range 0.03–0.47). A 5-year backtest shows a typical error of ±157.4%, with 80% of held-out values landing inside the 95% band.

+30%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 →
0.25Projected 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 →
0.03–0.4795% 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 →
±157.4%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, Pied-billed Grebe in Great Basin is projected to rise about 30% by 2030 — from 0.19 in 2025 to a central estimate of 0.25 (95% range 0.03–0.47). A 5-year backtest shows a typical error of ±157.4%, with 80% of held-out values landing inside the 95% band.19682030
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 →
20260.250.030.47
20270.250.030.47
20280.250.030.47
20290.250.030.47
20300.250.030.47

Routes In Great Basin

Routes recording Pied-billed 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 →
Crowder FlatCALIFORNIA122018
CortezNEVADA62025
BrewsterWASHINGTON62018
IngallsCALIFORNIA51994
DorrisCALIFORNIA52019
Barnes ValOREGON51987
EwanWASHINGTON42019
OthelloWASHINGTON41991
Lone RockOREGON32015
Davis LakeOREGON32025
Warner VallyOREGON32024
Bear RiverUTAH32025
Iron GateCALIFORNIA22019
TriangleIDAHO22021
Blackft ResIDAHO21998
Cedar HillIDAHO22016
Daniels ResIDAHO22025
Dobbin CreekNEVADA22018
Modoc Point 2OREGON22025
Lapham Res.OREGON22025
MerrillOREGON22013
Catlow RimOREGON22025
PromontoryUTAH22025
GoshenUTAH22006
LynnUTAH22013

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