BirdAnalyst
Species · Montana · BBS 2025 Release · 1966–2024

Eared Grebe Population Trend in Montana

All statesWetland birds

Eared Grebe in Montana has increased: up 49% on the route-weighted index since 1974.

+49%Since 1974TrendPercent 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 →
33Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
47YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Eared Grebe Trends in MontanaNotable 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 Eared Grebe in Montana. See the full index history below.

Eared Grebe Population Forecast in Montana

If the recent trend holds, Eared Grebe in Montana is projected to fall about 16% by 2029 — from 0.52 in 2024 to a central estimate of 0.44 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±94.5%, with 60% of held-out values landing inside the 95% band.

-16%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 →
0.44Projected 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 →
0.00–2.195% 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 →
±94.5%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, Eared Grebe in Montana is projected to fall about 16% by 2029 — from 0.52 in 2024 to a central estimate of 0.44 (95% range 0.00–2.1). A 5-year backtest shows a typical error of ±94.5%, with 60% of held-out values landing inside the 95% band.19702029
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 →
20250.470.002.2
20260.460.002.2
20270.460.002.1
20280.450.002.1
20290.440.002.1

Eared Grebe Survey Routes in Montana

Routes recording Eared Grebe in Montana.
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 →
Westby12120232015
Hebgen Lake3220222017
Two Dot1920241987
Highwood1820131970
Wheat Basin1420242018
Savage819871978
Virgelle620181979
Glasgow419821979
Ester Lake420242023
Sunburst320061975
Cleveland320101979
Malta320241976
Ingomar320231971
Dinosaurs H.M.320212019
Augusta220152013
Great Falls220182001
Roy220082008
Brusett219891989
Shawmut220241979
Red Rock220101990
Whitlash220242012
Kalispell120121974
St Mary119811970
Hay Lake120121990
Oswego120021995

Eared Grebe Population Trend in Other States

arizonacaliforniacoloradoidahoiowakansasminnesotanebraskanevadanew-mexiconorth-dakotaoklahomaoregonsouth-dakotatexasutahwashingtonwyoming

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