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

Common Merganser In BCR 4

All regionsBCR 4Waterfowl

Common Merganser in BCR 4 has surged: up 320% on the route-weighted index since 1987.

+320%Since 1987
19Routes In Region
29Years

Notable Signals

long arc increasecomputed index

Common Merganser has surged in BCR 4: up 320% on the route-weighted index since 1987.

Forecast

If the recent trend holds, Common Merganser in BCR 4 is projected to fall about 11% by 2029 — from 0.39 in 2024 to a central estimate of 0.35 (95% range 0.09–0.61). A 5-year backtest shows a typical error of ±51.1%, with 80% of held-out values landing inside the 95% band.

-11%Change by 2029
0.35Projected 2029 index
0.09–0.6195% range
±51.1%Backtest error
19822029
Projection of the recent trend (dashed) with 80/95% bands — a projection, not a prediction. Habitat, climate, and land use are not modeled.
YearProjected index95% low95% high
20250.330.060.59
20260.330.070.59
20270.340.070.60
20280.340.080.60
20290.350.090.61

Routes In BCR 4

Routes recording Common Merganser in BCR 4.
Anvik RiverALASKA82024
Burma RoadALASKA42009
Unalakleet RiverALASKA32024
Ft. RichrdsnALASKA32000
CircleALASKA22022
Chatanika RALASKA22023
ChistochinaALASKA22008
MonahanALASKA22010
Anchor RiverALASKA22023
PetersvilleALASKA22003
Seven LakesALASKA22022
Kanuti CanynALASKA22024
KalifonskyALASKA11982
Kenny LakeALASKA11998
Hatcher PassALASKA12009
Chena Hot Spring 2ALASKA12024
Hather CreekALASKA12011
TatalinaALASKA12009
Paxson LakeALASKA11992

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