BirdAnalyst
Species · Idaho · BBS 2026 Release · 1966–2025

Bufflehead Population Trend in Idaho

All statesWaterfowl

Bufflehead in Idaho has fallen sharply: down 62% on the route-weighted index since 1987.

-62%Since 1987TrendPercent 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 →
10Routes 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 →
18YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Bufflehead Trends in IdahoNotable 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 →

Bufflehead has fallen sharply in Idaho: down 62% on the route-weighted index since 1987.

Bufflehead Population Forecast in Idaho

If the recent trend holds, Bufflehead in Idaho is projected to stay roughly flat through 2029, near 0.05 (95% range 0.00–0.20). A 5-year backtest shows a typical error of ±73.4%, with 80% of held-out values landing inside the 95% band.

n/aChange 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 →
0.05Projected 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 →
0.00–0.2095% 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 →
±73.4%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, Bufflehead in Idaho is projected to stay roughly flat through 2029, near 0.05 (95% range 0.00–0.20). A 5-year backtest shows a typical error of ±73.4%, with 80% of held-out values landing inside the 95% band.19782029
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 →
20250.060.000.21
20260.060.000.21
20270.060.000.21
20280.050.000.21
20290.050.000.20

Bufflehead Survey Routes in Idaho

Routes recording Bufflehead in Idaho.
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 →
Salmon River820022002
Naples620161981
Iron Springs420181999
Lolo Pass320192000
Carey219991999
Springfield219781978
Blackft Res119871987
Cabarton120242002
Burgdorf120032003
Pasadena Val119911991

Bufflehead Population Trend in Other States

alaskacaliforniacoloradominnesotamontananevadanorth-dakotaoregonsouth-dakotautahwashingtonwisconsinwyoming

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