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Species · Montana · BBS 2025 Release · 1966–2024

Common Goldeneye Population Trend in Montana

All statesWaterfowl

Common Goldeneye in Montana has collapsed: down 77% on the route-weighted index since 1979.

-77%Since 1979TrendPercent 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 →
14Routes 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 →
29YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Common Goldeneye 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 →

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 →

Common Goldeneye has collapsed in Montana: down 77% on the route-weighted index since 1979.

Common Goldeneye Population Forecast in Montana

If the recent trend holds, Common Goldeneye in Montana is projected to stay roughly flat through 2028, near 0.03 (95% range 0.00–0.09). A 5-year backtest shows a typical error of ±160.4%, with 100% of held-out values landing inside the 95% band.

n/aChange by 2028TrendPercent 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 →
0.03Projected 2028 indexProjected indexThe central forecast of the abundance index if the recent trend continues. A projection of the current trajectory, not a prediction.Full methodology →
0.00–0.0995% 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 →
±160.4%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, Common Goldeneye in Montana is projected to stay roughly flat through 2028, near 0.03 (95% range 0.00–0.09). A 5-year backtest shows a typical error of ±160.4%, with 100% of held-out values landing inside the 95% band.19742028
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 →
20240.030.000.09
20250.030.000.09
20260.030.000.09
20270.030.000.09
20280.030.000.09

Common Goldeneye Survey Routes in Montana

Routes recording Common Goldeneye 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 →
Dinosaurs H.M.720192019
Kalispell220141974
St Mary220002000
Whitefish Lake220232021
Beaverhead219741974
Elliston220141987
Noxon120182018
Glasgow119791979
Arlee120132013
Augusta120152015
East Glacier Park120152015
Saco120172017
Brusett119891989
Circle119781978

Common Goldeneye Population Trend in Other States

alaskacaliforniaidahomainemichiganminnesotanew-hampshirenew-yorknorth-dakotavermontwashingtonwisconsinwyoming

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