BirdAnalyst
Species · BCR 9 · BBS 2025 Release · 1966–2024

Bufflehead In Great Basin

All regionsGreat BasinWaterfowl

Bufflehead in Great Basin has collapsed: down 77% on the route-weighted index since 1971.

-77%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 →
27Routes 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 →
47YearsYears 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 collapsed in Great Basin: down 77% 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 27% by 2029 — from 0.09 in 2024 to a central estimate of 0.06 (95% range 0.00–0.28). A 5-year backtest shows a typical error of ±41.6%, with 100% of held-out values landing inside the 95% band.

-27%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 →
0.06Projected 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 →
0.00–0.2895% 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 →
±41.6%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, Bufflehead in Great Basin is projected to fall about 27% by 2029 — from 0.09 in 2024 to a central estimate of 0.06 (95% range 0.00–0.28). A 5-year backtest shows a typical error of ±41.6%, with 100% of held-out values landing inside the 95% band.19692029
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 →
20250.070.000.29
20260.070.000.29
20270.070.000.29
20280.060.000.28
20290.060.000.28

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
Catlow RimOREGON82024
DeschutesOREGON72022
Bald Mtn.NEVADA62018
Iron SpringsIDAHO42018
Barnes ValOREGON41987
Clear Lk ResCALIFORNIA22018
Crowder FlatCALIFORNIA22013
MadelineCALIFORNIA22024
Iron GateCALIFORNIA22016
SpringfieldIDAHO21978
CareyIDAHO21999
Bly 2OREGON22019
NubieberCALIFORNIA11995
Davis CreekCALIFORNIA12012
Pasadena ValIDAHO11991
Blackft ResIDAHO11987
Dell SpringOREGON11990
Blizzard GapOREGON12022
Lapham Res.OREGON12024
MerrillOREGON12012
Warner VallyOREGON12024
ConnellWASHINGTON11994

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