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

Lesser Scaup Population Trend in Washington

All statesWaterfowl

Lesser Scaup in Washington has fallen sharply: down 60% on the route-weighted index since 1981.

-60%Since 1981TrendPercent 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 →
15Routes 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 →
42YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Lesser Scaup Trends in WashingtonNotable 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 →

Lesser Scaup has fallen sharply in Washington: down 60% on the route-weighted index since 1981.

Lesser Scaup Population Forecast in Washington

If the recent trend holds, Lesser Scaup in Washington is projected to fall about 100% by 2028 — from 0.05 in 2023 to a central estimate of 0.00 (95% range 0.00–0.80). A 5-year backtest shows a typical error of ±74.7%, with 100% of held-out values landing inside the 95% band.

-100%Change 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 →
0.00Projected 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 →
0.00–0.8095% 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 →
±74.7%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, Lesser Scaup in Washington is projected to fall about 100% by 2028 — from 0.05 in 2023 to a central estimate of 0.00 (95% range 0.00–0.80). A 5-year backtest shows a typical error of ±74.7%, with 100% of held-out values landing inside the 95% band.19752028
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 →
20240.000.000.80
20250.000.000.80
20260.000.000.80
20270.000.000.80
20280.000.000.80

Lesser Scaup Survey Routes in Washington

Routes recording Lesser Scaup in Washington.
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 →
Brewster820141981
Columbia Nwr620031992
Ellensburg520081994
Mendota 2420002000
Harrington420011999
Quincy319981992
Selah320122012
Rimrock319921992
Potholes320232005
Reardan220081977
Carlton220141997
Twin Lakes219961996
Wilbur120041984
Connell119751975
Tonasket120181989

Lesser Scaup Population Trend in Other States

alaskacaliforniacoloradoidahoiowakansasmichiganminnesotamontananebraskanevadanew-mexiconorth-dakotaoregonsouth-dakotautahwisconsinwyoming

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