BirdAnalyst
Species · North Dakota · BBS 2025 Release · 1966–2024

Bufflehead Population Trend in North Dakota

All statesWaterfowl

Bufflehead in North Dakota has surged: up 11× on the route-weighted index since 1985.

11×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 →
38YearsYears 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 11× 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 58% by 2029 — from 2.6 in 2024 to a central estimate of 1.1 (95% range 0.07–2.2). A 5-year backtest shows a typical error of ±55.8%, with 40% of held-out values landing inside the 95% band.

-58%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 →
1.1Projected 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 →
0.07–2.295% 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 →
±55.8%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 58% by 2029 — from 2.6 in 2024 to a central estimate of 1.1 (95% range 0.07–2.2). A 5-year backtest shows a typical error of ±55.8%, with 40% of held-out values landing inside the 95% band.19802029
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 →
20251.00.002.1
20261.00.002.1
20271.10.022.1
20281.10.052.1
20291.10.072.2

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 Lk5520241998
Wild Rose620241997
Turtle Mtns420241980
Danzig320102000
Cooperstown320132010
Lake George220192019
Douglas Crk220242024
Sheyenne Lk220241994
Rolla220242004
Braddock120211996
Dunn Center119941994

Bufflehead Population Trend in Other States

alaskacaliforniacoloradoidahominnesotamontananevadaoregonsouth-dakotautahwashingtonwisconsinwyoming

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