BirdAnalyst
Species · BCR 16 · BBS 2025 Release · 1966–2024

Lesser Scaup In Southern Rockies / Colorado Plateau

All regionsSouthern Rockies / Colorado PlateauWaterfowl

Lesser Scaup in Southern Rockies / Colorado Plateau has surged: up 369% on the route-weighted index since 1982.

+369%Since 1982TrendPercent 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 →
29Routes 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 →
41YearsYears 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 Southern Rockies / Colorado Plateau: up 369% on the route-weighted index since 1982.

Lesser Scaup In Southern Rockies / Colorado Plateau Population Forecast

If the recent trend holds, Lesser Scaup in Southern Rockies / Colorado Plateau is projected to fall about 14% by 2029 — from 0.67 in 2024 to a central estimate of 0.58 (95% range 0.18–0.98). A 5-year backtest shows a typical error of ±20.2%, with 100% of held-out values landing inside the 95% band.

-14%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 →
0.58Projected 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 →
0.18–0.9895% 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 →
±20.2%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 Southern Rockies / Colorado Plateau is projected to fall about 14% by 2029 — from 0.67 in 2024 to a central estimate of 0.58 (95% range 0.18–0.98). A 5-year backtest shows a typical error of ±20.2%, with 100% of held-out values landing inside the 95% band.19682029
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 →
20250.560.160.95
20260.560.170.96
20270.570.170.97
20280.580.180.97
20290.580.180.98

Routes In Southern Rockies / Colorado Plateau

Routes recording Lesser Scaup in Southern Rockies / Colorado Plateau.
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 →
Rio Grnds RsCOLORADO782024
Mcphee Res.COLORADO122012
DinosaurCOLORADO102012
Angel Fire 2NEW-MEXICO62009
Skyline DrivUTAH62002
M Warner ResUTAH62024
VernalUTAH42016
WarbonnetWYOMING42017
Willow PeakCOLORADO32018
TincupCOLORADO32024
Main CanyonUTAH32018
Moon LakeUTAH32000
ColonaCOLORADO22014
WaldenCOLORADO22016
Dunckley PasCOLORADO22017
PiedraCOLORADO22023
Uintah NfUTAH21992
BrookhurstWYOMING21992
Lost LakeCOLORADO12002
TarryallCOLORADO11989
DoylevilleCOLORADO12012
Groundhog RsCOLORADO11995
Ragged Mtn.COLORADO12006
Yellowjacket PassCOLORADO12022
Stillwater PassCOLORADO11999

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