Bird Conservation Region 4

BCR 4

An ecological region spanning Alaska, with 70 survey routes. BCRs are the natural unit for bird trends.

What Is Moving Here

long arc declinecomputed index

Glaucous Gull has collapsed in BCR 4: down 100% on the route-weighted index since 1991.

long arc increasecomputed index

Greater White-fronted Goose has surged in BCR 4: up 608% on the route-weighted index since 1991.

long arc declinecomputed index

Glaucous-winged Gull has collapsed in BCR 4: down 99% on the route-weighted index since 1982.

long arc increasecomputed index

Red-breasted Nuthatch has surged in BCR 4: up 587% on the route-weighted index since 1994.

long arc declinecomputed index

Lapland Longspur has collapsed in BCR 4: down 98% on the route-weighted index since 1986.

long arc increasecomputed index

Red-breasted Merganser has surged in BCR 4: up 382% on the route-weighted index since 1991.

How Guilds Are Faring

Survey Routes

Species By Family

Osprey Pandionidae

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