Bird Conservation Region 12

Boreal Hardwood Transition

An ecological region spanning Michigan, Minnesota, Wisconsin, with 127 survey routes. BCRs are the natural unit for bird trends.

What Is Moving Here

long arc declinecomputed index

Purple Martin has collapsed in Boreal Hardwood Transition: down 98% on the route-weighted index since 1968.

long arc increasecomputed index

Canada Goose has surged in Boreal Hardwood Transition: up 58× on the route-weighted index since 1973.

long arc declinecomputed index

Herring Gull has collapsed in Boreal Hardwood Transition: down 96% on the route-weighted index since 1968.

long arc increasecomputed index

Sandhill Crane has surged in Boreal Hardwood Transition: up 43× on the route-weighted index since 1969.

long arc declinecomputed index

Cliff Swallow has collapsed in Boreal Hardwood Transition: down 93% on the route-weighted index since 1968.

long arc increasecomputed index

Wild Turkey has surged in Boreal Hardwood Transition: up 22× on the route-weighted index since 1970.

How Guilds Are Faring

Survey Routes

Species By Family

Osprey Pandionidae

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