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

Pied-billed Grebe In Northern Rockies

All regionsNorthern RockiesWetland birds

Pied-billed Grebe in Northern Rockies has declined: down 39% on the route-weighted index since 1973.

-39%Since 1973TrendPercent 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 →
49Routes 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 →
53YearsYears 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 →

No notable trend signals for Pied-billed Grebe in Northern Rockies. See the full index history below.

Pied-billed Grebe In Northern Rockies Population Forecast

If the recent trend holds, Pied-billed Grebe in Northern Rockies is projected to fall about 29% by 2029 — from 0.16 in 2024 to a central estimate of 0.11 (95% range 0.00–0.25). A 5-year backtest shows a typical error of ±71.7%, with 100% of held-out values landing inside the 95% band.

-29%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 →
0.11Projected 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 →
0.00–0.2595% 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 →
±71.7%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 Northern Rockies is projected to fall about 29% by 2029 — from 0.16 in 2024 to a central estimate of 0.11 (95% range 0.00–0.25). A 5-year backtest shows a typical error of ±71.7%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20250.120.000.26
20260.110.000.26
20270.110.000.26
20280.110.000.25
20290.110.000.25

Routes In Northern Rockies

Routes recording Pied-billed 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 →
Rawlins 2WYOMING122016
NaplesIDAHO92024
KalispellMONTANA42024
Great DivideCOLORADO32016
AugustaMONTANA32024
Saleratus CrUTAH32016
TensleepWYOMING32015
Browns ParkCOLORADO22005
CabartonIDAHO22004
RandolphUTAH22021
ChewelahWASHINGTON22008
Omak CreekWASHINGTON22024
LamontWYOMING21999
Green RiverWYOMING21982
LayCOLORADO12000
MivodenIDAHO12006
CentervilleIDAHO12008
St MaryMONTANA11995
PolsonMONTANA11994
ArleeMONTANA11990
ChestnutMONTANA12024
BeaverheadMONTANA12024
GlenMONTANA12019
Willow Creek 2MONTANA12006
Swan LakeMONTANA12018

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