BirdAnalyst
Species · BCR 9 · BBS 2026 Release · 1966–2025

Lesser Scaup In Great Basin

All regionsGreat BasinWaterfowl

Lesser Scaup in Great Basin has surged: up 171% on the route-weighted index since 1971.

+171%Since 1971TrendPercent 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 →
62Routes In RegionSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
56YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable SignalsNotable 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 →

Lesser Scaup has surged in Great Basin: up 171% on the route-weighted index since 1971.

Lesser Scaup In Great Basin Population Forecast

If the recent trend holds, Lesser Scaup in Great Basin is projected to rise about 261% by 2030 — from 0.28 in 2025 to a central estimate of 0.99 (95% range 0.00–2.6). A 5-year backtest shows a typical error of ±262.7%, with 100% of held-out values landing inside the 95% band.

+261%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 →
0.99Projected 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 →
0.00–2.695% 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 →
±262.7%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 Great Basin is projected to rise about 261% by 2030 — from 0.28 in 2025 to a central estimate of 0.99 (95% range 0.00–2.6). A 5-year backtest shows a typical error of ±262.7%, with 100% of held-out values landing inside the 95% band.19682030
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 →
20261.00.002.7
20271.00.002.7
20281.00.002.7
20291.000.002.7
20300.990.002.6

Routes In Great Basin

Routes recording Lesser Scaup in Great Basin.
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 SpringsIDAHO382024
DorrisCALIFORNIA172019
Blackft ResIDAHO152018
Mud LakeIDAHO122025
Blizzard GapOREGON102017
Crowder FlatCALIFORNIA82019
Modoc Point 2OREGON82025
BrewsterWASHINGTON82014
PrincetonOREGON71975
Catlow RimOREGON72025
Ruby Valley 2NEVADA62016
Columbia NwrWASHINGTON62003
Modoc PointOREGON52009
Fish LakeOREGON52025
LynnUTAH52021
EllensburgWASHINGTON52008
Cedar HillIDAHO42024
Dobbin CreekNEVADA41985
Bald Mtn.NEVADA42025
HarringtonWASHINGTON42001
Blacks CreekIDAHO31982
RimrockWASHINGTON31992
QuincyWASHINGTON31998
PotholesWASHINGTON32023
SelahWASHINGTON32012

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