BirdAnalyst
Species · BCR 10 · BBS 2026 Release · 1966–2025

Lesser Scaup In Northern Rockies

All regionsNorthern RockiesWaterfowl

Lesser Scaup in Northern Rockies has surged: up 326% on the route-weighted index since 1977.

+326%Since 1977TrendPercent 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 →
58Routes 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 →
50YearsYears 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 Northern Rockies: up 326% on the route-weighted index since 1977.

Lesser Scaup In Northern Rockies Population Forecast

If the recent trend holds, Lesser Scaup in Northern Rockies is projected to rise about 34% by 2030 — from 0.57 in 2025 to a central estimate of 0.76 (95% range 0.00–2.0). A 5-year backtest shows a typical error of ±108.2%, with 100% of held-out values landing inside the 95% band.

+34%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 →
0.76Projected 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 →
0.00–2.095% 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 →
±108.2%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 Northern Rockies is projected to rise about 34% by 2030 — from 0.57 in 2025 to a central estimate of 0.76 (95% range 0.00–2.0). A 5-year backtest shows a typical error of ±108.2%, with 100% of held-out values landing inside the 95% band.19702030
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 →
20260.770.002.0
20270.770.002.0
20280.760.002.0
20290.760.002.0
20300.760.002.0

Routes In Northern Rockies

Routes recording Lesser Scaup in Northern Rockies.
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 →
Hayden ValWYOMING291986
YellowstoneWYOMING282025
MammothWYOMING242025
Rawlins 2WYOMING222025
ClarkWYOMING122001
Rock RiverWYOMING82022
Red RockMONTANA72025
Clover CreekOREGON61997
Willow Creek 2MONTANA52006
Neponset ResUTAH52017
WalcottWYOMING52025
CentervilleIDAHO42010
Sawtooth City 2IDAHO42017
St MaryMONTANA41997
AugustaMONTANA42024
East Glacier ParkMONTANA42019
Hunter PeakWYOMING42024
SeedskadeeWYOMING41997
NaplesIDAHO31977
FontenelleWYOMING31987
ErvayWYOMING32018
Crazy WomanWYOMING32010
Fiddler LkWYOMING32011
CascadeIDAHO21978
CabartonIDAHO22022

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