BirdAnalyst
Species · BCR 4 · BBS 2025 Release · 1966–2024

Bufflehead In BCR 4

All regionsBCR 4Waterfowl

Bufflehead in BCR 4 has declined: down 38% on the route-weighted index since 1987.

-38%Since 1987TrendPercent 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 →
35Routes 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 →
37YearsYears 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 →

No notable trend signals for Bufflehead in BCR 4. See the full index history below.

Bufflehead In BCR 4 Population Forecast

If the recent trend holds, Bufflehead in BCR 4 is projected to fall about 29% by 2029 — from 0.44 in 2024 to a central estimate of 0.32 (95% range 0.00–0.84). A 5-year backtest shows a typical error of ±22.5%, with 100% of held-out values landing inside the 95% band.

-29%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 →
0.32Projected 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 →
0.00–0.8495% 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 →
±22.5%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 BCR 4 is projected to fall about 29% by 2029 — from 0.44 in 2024 to a central estimate of 0.32 (95% range 0.00–0.84). A 5-year backtest shows a typical error of ±22.5%, with 100% of held-out values landing inside the 95% band.19832029
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 →
20250.340.000.86
20260.330.000.86
20270.330.000.85
20280.320.000.85
20290.320.000.84

Routes In BCR 4

Routes recording Bufflehead in BCR 4.
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 →
Porcupine R.ALASKA102002
MonahanALASKA82017
Bear CreekALASKA61990
Nicholai SlALASKA62022
ChickenALASKA41994
DeltaALASKA42024
Mccarthy Rd2ALASKA42017
SlanaALASKA32024
ColdfootALASKA32023
Koyukuk Riv.ALASKA32001
Kanuti LakeALASKA32024
CircleALASKA22023
ToklatALASKA22019
Kanuti CanynALASKA22024
Mud RiverALASKA22024
Birch LakeALASKA12013
LivengoodALASKA12018
ChistochinaALASKA12001
NorthwayALASKA12023
CantwellALASKA12000
WillowALASKA12022
L SalchaALASKA12001
Chena Hot SpALASKA11990
Kenny LakeALASKA12008
SourdoughALASKA12024

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