BirdAnalyst
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 HereNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

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

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

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

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

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

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

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

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

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

long arc increasecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

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

How Guilds Are FaringGuild trendA mean-index aggregate across the species in this group — the structural direction of the guild, with individual-species noise smoothed out.Full methodology →

-85%

Seabirds

1 species
-83%

Grassland birds

6 species
-76%

Birds of prey

16 species
-72%

Aerial insectivores

10 species
-71%

Game birds

3 species
-63%

Waterfowl

20 species
-52%

Wetland birds

15 species
-47%

Forest birds

38 species
-30%

Shorebirds

10 species
+28%

Generalists

3 species

Survey Routes

Species By FamilyTrendPercent 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 →

Hawks, Eagles & Kites Accipitridae

American Goshawk -65%Bald Eagle +31%Golden Eagle -65%Northern Harrier -66%Red-tailed Hawk -26%Rough-legged Hawk -4%Sharp-shinned Hawk -80%

Larks Alaudidae

Horned Lark -77%

Kingfishers Alcedinidae

Belted Kingfisher -66%

Ducks, Geese & Waterfowl Anatidae

American Wigeon +224%Barrow's Goldeneye -73%Bufflehead -38%Canada Goose -25%Common Goldeneye -4%Common Merganser +320%Greater Scaup -82%Greater White-fronted Goose +608%Green-winged Teal +100%Harlequin Duck +49%Lesser Scaup -44%Long-tailed Duck -87%Mallard -78%Northern Pintail -61%Northern Shoveler -51%Red-breasted Merganser +382%Ring-necked Duck +15%Trumpeter Swan +133%Tundra Swan +63%White-winged Scoter -22%

Waxwings Bombycillidae

Bohemian Waxwing -67%

Longspurs & Snow Buntings Calcariidae

Lapland Longspur -99%

Treecreepers Certhiidae

Brown Creeper -67%

Plovers & Lapwings Charadriidae

American Golden-Plover -97%Semipalmated Plover -87%

Crows, Jays & Magpies Corvidae

American Crow +61%Black-billed Magpie +98%Canada Jay +44%Common Raven +64%Steller's Jay -90%

Falcons & Caracaras Falconidae

American Kestrel -21%Merlin +23%Peregrine Falcon +263%

Finches Fringillidae

Pine Grosbeak -66%Pine Siskin -91%White-winged Crossbill +236%

Loons Gaviidae

Common Loon -49%Pacific Loon -65%Red-throated Loon +114%

Cranes Gruidae

Sandhill Crane +125%

Swallows & Martins Hirundinidae

Bank Swallow -79%Cliff Swallow -75%Tree Swallow -83%Violet-green Swallow +70%

Blackbirds & Orioles Icteridae

Red-winged Blackbird -55%Rusty Blackbird -15%

Shrikes Laniidae

Northern Shrike -83%

Gulls, Terns & Skimmers Laridae

Arctic Tern -84%Bonaparte's Gull -71%Glaucous Gull -100%Glaucous-winged Gull -99%Herring Gull +53%Short-billed Gull -37%

Wagtails & Pipits Motacillidae

American Pipit -92%

Osprey Pandionidae

Osprey +291%

Chickadees & Titmice Paridae

Black-capped Chickadee -53%Boreal Chickadee +137%

Wood-Warblers Parulidae

Blackpoll Warbler +57%Common Yellowthroat +171%Northern Waterthrush +5%Orange-crowned Warbler +70%Tennessee Warbler -80%Townsend's Warbler +49%Wilson's Warbler +22%Yellow Warbler -23%

New World Sparrows Passerellidae

American Tree Sparrow +227%Chipping Sparrow +1%Fox Sparrow -38%Golden-crowned Sparrow +4%Lincoln's Sparrow +109%Savannah Sparrow -66%Song Sparrow -98%White-crowned Sparrow -17%

Pheasants, Grouse & Turkeys Phasianidae

Ruffed Grouse +41%Spruce Grouse -66%Willow Ptarmigan -54%

Leaf Warblers Phylloscopidae

Arctic Warbler -56%

Woodpeckers Picidae

American Three-toed Woodpecker +50%Black-backed Woodpecker +385%Downy Woodpecker -18%Hairy Woodpecker -69%

Grebes Podicipedidae

Horned Grebe -89%Red-necked Grebe -74%

Kinglets Regulidae

Golden-crowned Kinglet +85%Ruby-crowned Kinglet +25%

Sandpipers & Allies Scolopacidae

Greater Yellowlegs -67%Least Sandpiper -43%Lesser Yellowlegs -21%Red-necked Phalarope -96%Solitary Sandpiper +93%Spotted Sandpiper +200%Upland Sandpiper -88%Whimbrel -74%Wilson's Snipe +104%

Nuthatches Sittidae

Red-breasted Nuthatch +587%

Skuas & Jaegers Stercorariidae

Long-tailed Jaeger -85%

Owls Strigidae

Boreal Owl -78%Great Gray Owl +35%Great Horned Owl -37%Northern Hawk Owl -60%Short-eared Owl -74%

Thrushes Turdidae

American Robin -23%Gray-cheeked Thrush -58%Hermit Thrush +72%Swainson's Thrush +14%Townsend's Solitaire +28%Varied Thrush -14%

Tyrant Flycatchers Tyrannidae

Alder Flycatcher -36%Hammond's Flycatcher +225%Olive-sided Flycatcher +50%Say's Phoebe -95%Western Wood-Pewee +105%Yellow-bellied Flycatcher 18×

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