BirdAnalyst
Species · BCR 4 · BBS 2026 Release · 1966–2025

Bufflehead In BCR 4

All regionsBCR 4Waterfowl

Bufflehead in BCR 4 has declined: down 32% on the route-weighted index since 1987.

-32%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 →
38YearsYears 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 54% by 2030 — from 0.78 in 2025 to a central estimate of 0.36 (95% range 0.00–0.90). A 5-year backtest shows a typical error of ±33.6%, with 100% of held-out values landing inside the 95% band.

-54%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 →
0.36Projected 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 →
0.00–0.9095% 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 →
±33.6%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 BCR 4 is projected to fall about 54% by 2030 — from 0.78 in 2025 to a central estimate of 0.36 (95% range 0.00–0.90). A 5-year backtest shows a typical error of ±33.6%, with 100% of held-out values landing inside the 95% band.19832030
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 →
20260.380.000.91
20270.370.000.91
20280.370.000.91
20290.370.000.90
20300.360.000.90

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 →
Nicholai SlALASKA162025
Porcupine R.ALASKA102002
Chena Hot Spring 2ALASKA92025
MonahanALASKA82017
Bear CreekALASKA61990
ChickenALASKA41994
ColdfootALASKA42025
DeltaALASKA42024
Mccarthy Rd2ALASKA42017
SlanaALASKA32024
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

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