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

Bufflehead In Great Basin

All regionsGreat BasinWaterfowl

Bufflehead in Great Basin has fallen sharply: down 65% on the route-weighted index since 1971.

-65%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 →
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 →
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 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 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 →

Bufflehead has fallen sharply in Great Basin: down 65% on the route-weighted index since 1971.

Bufflehead In Great Basin Population Forecast

If the recent trend holds, Bufflehead in Great Basin is projected to fall about 58% by 2030 — from 0.17 in 2025 to a central estimate of 0.07 (95% range 0.00–0.29). A 5-year backtest shows a typical error of ±45.7%, with 100% of held-out values landing inside the 95% band.

-58%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 →
0.07Projected 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 →
0.00–0.2995% 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 →
±45.7%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, Bufflehead in Great Basin is projected to fall about 58% by 2030 — from 0.17 in 2025 to a central estimate of 0.07 (95% range 0.00–0.29). A 5-year backtest shows a typical error of ±45.7%, with 100% of held-out values landing inside the 95% band.19692030
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 →
20260.070.000.29
20270.070.000.29
20280.070.000.29
20290.070.000.29
20300.070.000.29

Routes In Great Basin

Routes recording Bufflehead 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 →
BrewsterWASHINGTON222008
Modoc PointOREGON182000
DorrisCALIFORNIA142017
Lapham Res.OREGON102025
Catlow RimOREGON82024
DeschutesOREGON72022
MadelineCALIFORNIA62025
Bald Mtn.NEVADA62018
Iron SpringsIDAHO42018
Barnes ValOREGON41987
Bly 2OREGON32025
Clear Lk ResCALIFORNIA22018
Crowder FlatCALIFORNIA22013
Iron GateCALIFORNIA22016
SpringfieldIDAHO21978
CareyIDAHO21999
Trout CreekOREGON22025
NubieberCALIFORNIA11995
LikelyCALIFORNIA12025
Davis CreekCALIFORNIA12012
Pasadena ValIDAHO11991
Blackft ResIDAHO11987
Dell SpringOREGON11990
Blizzard GapOREGON12022
MerrillOREGON12012

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