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

Lesser Scaup Population Trend in Idaho

All statesWaterfowl

Lesser Scaup in Idaho has increased: up 43% on the route-weighted index since 1973.

+43%Since 1973TrendPercent 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 →
21Routes 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 →
48YearsYears 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 IdahoNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

No notable trend signals for Lesser Scaup in Idaho. See the full index history below.

Lesser Scaup Population Forecast in Idaho

If the recent trend holds, Lesser Scaup in Idaho is projected to fall about 20% by 2029 — from 1.7 in 2024 to a central estimate of 1.3 (95% range 0.20–2.5). A 5-year backtest shows a typical error of ±20.6%, with 100% of held-out values landing inside the 95% band.

-20%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 →
1.3Projected 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 →
0.20–2.595% 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 →
±20.6%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 Idaho is projected to fall about 20% by 2029 — from 1.7 in 2024 to a central estimate of 1.3 (95% range 0.20–2.5). A 5-year backtest shows a typical error of ±20.6%, with 100% of held-out values landing inside the 95% band.19712029
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 →
20251.30.172.5
20261.30.172.5
20271.30.182.5
20281.30.192.5
20291.30.202.5

Lesser Scaup Survey Routes in Idaho

Routes recording Lesser Scaup 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 →
Iron Springs3820241988
Mud Lake1620231988
Blackft Res1520181984
Centerville420101992
Sawtooth City 2420172017
Cedar Hill420242015
Naples319771977
Blacks Creek319821973
Kyle Canyon219981996
Cascade219781977
Springfield220141971
Triangle220152006
Magic Mtn219991999
Crane Creek219941994
Picabo220091989
Bates220062005
Cabarton220222022
Pasadena Val220142003
Henry119781978
Featherville120132013
Dougal Res119981995

Lesser Scaup Population Trend in Other States

alaskacaliforniacoloradoiowakansasmichiganminnesotamontananebraskanevadanew-mexiconorth-dakotaoregonsouth-dakotautahwashingtonwisconsinwyoming

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