BirdAnalyst
Species · North Dakota · BBS 2026 Release · 1966–2025

Bufflehead Population Trend in North Dakota

All statesWaterfowl

Bufflehead in North Dakota has surged: up 12× on the route-weighted index since 1985.

12×Since 1985TrendPercent 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 →
11Routes 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 →
39YearsYears 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 North DakotaNotable 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 →

Bufflehead has surged in North Dakota: up 12× on the route-weighted index since 1985.

Bufflehead Population Forecast in North Dakota

If the recent trend holds, Bufflehead in North Dakota is projected to fall about 40% by 2030 — from 2.1 in 2025 to a central estimate of 1.3 (95% range 0.21–2.4). A 5-year backtest shows a typical error of ±58.5%, with 40% of held-out values landing inside the 95% band.

-40%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 →
1.3Projected 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 →
0.21–2.495% 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 →
±58.5%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, Bufflehead in North Dakota is projected to fall about 40% by 2030 — from 2.1 in 2025 to a central estimate of 1.3 (95% range 0.21–2.4). A 5-year backtest shows a typical error of ±58.5%, with 40% of held-out values landing inside the 95% band.19802030
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 →
20261.20.102.3
20271.20.132.3
20281.20.152.3
20291.30.182.3
20301.30.212.4

Bufflehead Survey Routes in North Dakota

Routes recording Bufflehead in North Dakota.
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 →
Horsehead Lk5020251998
Lake George1120232019
Wild Rose620241997
Danzig320102000
Sheyenne Lk320251994
Turtle Mtns320251980
Cooperstown220252010
Douglas Crk220242024
Rolla220242004
Braddock120211996
Dunn Center119941994

Bufflehead Population Trend in Other States

alaskacaliforniacoloradoidahominnesotamontananevadaoregonsouth-dakotautahwashingtonwisconsinwyoming

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