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
Purple Martin has collapsed in Boreal Hardwood Transition: down 98% on the route-weighted index since 1968.
Canada Goose has surged in Boreal Hardwood Transition: up 58× on the route-weighted index since 1973.
Herring Gull has collapsed in Boreal Hardwood Transition: down 96% on the route-weighted index since 1968.
Sandhill Crane has surged in Boreal Hardwood Transition: up 43× on the route-weighted index since 1969.
Cliff Swallow has collapsed in Boreal Hardwood Transition: down 93% on the route-weighted index since 1968.
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
Hawks, Eagles & Kites Accipitridae
Larks Alaudidae
Kingfishers Alcedinidae
Ducks, Geese & Waterfowl Anatidae
Swifts Apodidae
Waxwings Bombycillidae
Cardinals & Grosbeaks Cardinalidae
New World Vultures Cathartidae
Treecreepers Certhiidae
Plovers & Lapwings Charadriidae
Crows, Jays & Magpies Corvidae
Finches Fringillidae
Loons Gaviidae
Cranes Gruidae
Swallows & Martins Hirundinidae
Blackbirds & Orioles Icteridae
Gulls, Terns & Skimmers Laridae
New World Quail Odontophoridae
Osprey Pandionidae
Wood-Warblers Parulidae
New World Sparrows Passerellidae
Old World Sparrows Passeridae
Pelicans Pelecanidae
Cormorants Phalacrocoracidae
Pheasants, Grouse & Turkeys Phasianidae
Woodpeckers Picidae
Grebes Podicipedidae
Gnatcatchers Polioptilidae
Sandpipers & Allies Scolopacidae
Starlings & Mynas Sturnidae
Hummingbirds Trochilidae
Thrushes Turdidae
Tyrant Flycatchers Tyrannidae
Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.