Bird Conservation Areas
Bird Conservation Areas
Five
Bird Conservation Regions (BCRs) were designated in Alaska as part of the North
American Bird Conservation Initiative in order provide a framework that
would facilitate coordinated conservation and evaluations of major bird
initiatives. The BCRs roughly follow the Biogeographic Regions of Kessel and Gibson (1978). In some regions,
conservation actions, including monitoring, may be more appropriately considered
within a sub-region if management issues are similar within this unit (e.g.,
Cook Inlet). Below are descriptions of these 5 regions and delineations of
subregions within each; detailed descriptions are provided in Ecoregions of
Alaska by Gallant et al.
(1995).
Arctic Coastal Plain/Foothills - Northern Alaska
This region includes low-lying, coastal tundra and drier uplands of the Arctic Foothills of the Brooks Range. Sub-regions include : A) Arctic Coastal Plain, and B) Arctic Foothills and north slope of the Brooks Range. It extends from the Alaska-Canada border at Demarcation Point westward, and southward, to the mouth of the Noatak River. Because of thick, continuous permafrost, surface water dominates the landscape (20-50% of the land surface on the coastal plain). Freezing and thawing form a patterned mosaic of polygonal ridges and ponds. Several rivers (e.g., Colville River) bisect the plain and flow into the Arctic Ocean. Barrow, lying near the Arctic Ocean, experiences 67 days of darkness in the winter and 84 days of continuous sunlight in the summer. The ocean surface, except for leads, is frozen 9 to 10 months a year, and the ice pack is never far from shore. Because of the wetness, waterfowl and shorebirds dominate the breeding avian community and passerines are scarce. The most abundant breeding birds on the coastal plain include the: Northern Pintail, King Eider, Oldsquaw, American Golden-Plover, Semipalmated Sandpiper, Pectoral Sandpiper, Red-necked Phalarope, and Lapland Longspur. Few bird species winter in the region. Several Old World species penetrate the region from the west (e.g., Arctic Warbler, Bluethroat), and species regularly breeding in the Canadian arctic penetrate from the east (e.g., White-rumped Sandpiper, Black Guillemot). Taiga passerines (e.g., Gray-cheeked Thrush, Yellow Warbler) reach the region along drainage systems from the Brooks Range and raptors nest commonly along major rivers (e.g., Gyrfalcon, Rough-legged Hawk).
Western Alaska - Includes portions of Western and Southwestern Alaska
This region consists of the coastal plain and mountains of
western and southwestern mainland Alaska. Sub-regions include: A) Subarctic
Coastal Plain and Seward Peninsula, B) Ahklun and Kilbuck Mountains and Bristol
Bay-Nushagak Lowlands, and C) Alaska Peninsula Mountains. Permafrost is
continuous except in southern parts of the region. Sea cliffs are present as are
mountains that exceed 3,300 feet (1,000 m) in elevation. Volcanic peaks up to
8,500 feet (2,600 m) are found along the Alaska Peninsula. Wet and mesic
graminoid herbaceous communities dominate the lowlands and numerous ponds,
lakes, and rivers dot the landscape. Tall shrub communities are found along
rivers and streams and low shrub communities occupy uplands; forests of spruce
and hardwoods penetrate the region on the eastern edge. High densities of
breeding waterfowl and shorebirds are found on the coastal plain of the Yukon
and Kuskokwim rivers. Intertidal areas here and lagoons of the north side of the
Alaska Peninsula supports millions of shorebirds during migration (e.g.,
Dunlins, Western Sandpipers, Red Knots,
Bar-tailed Godwits). The coast of the Alaska Peninsula supports high
concentrations of wintering sea ducks that include the: Steller’s Eider,
Harlequin, Oldsquaw, Surf Scoter, and Black Scoter. Western Alaska includes an
unique Beringian breeding avifaunal element (e.g., Black Turnstone, Bristle-thighed
Curlew) and several Old World species are regular breeders or migrants in this
region (e.g., Sharp-tailed Sandpiper, Red-throated Pipit, White Wagtail).
Passerine diversity is greatest in tall, riparian shrub habitats (e.g., Arctic
Warbler, Gray-cheeked Thrush, Blackpoll Warbler) and raptors (e.g., Gyrfalcon,
Rough-legged Hawk) nest along the riverine cliffs. Mainland sea cliffs contain
nesting colonies of, largely, Black-legged Kittiwakes, Common Murres, and
Pelagic Cormorants.
Aleutian/Bering Sea Islands - Includes portions of Western and Southwestern Alaska
Included in this
region are the Aleutian Islands, that extend westward from the Alaskan mainland
for 1,100 miles (1,800 km), and the Bering Sea islands (that include the
Pribilofs, St. Matthew, Hall, St. Lawrence, and Little Diomede). The Aleutian
chain is volcanic in origin. The climate is maritime and wind is ever present.
Sea ice does not extend to the Aleutians and permafrost is generally absent;
however, sea ice is an important feature of the Bering Sea. Vegetation at higher
elevations consists of dwarf shrub communities, mainly willow and crowberry.
Meadows and marshes of herbs, sedges, and grasses are plentiful and some islands
have ericaceous bogs. Seabirds are a dominant component of this region’s
avifauna and several species breed only in this region (e.g., Red-legged
Kittiwake, Least Auklet, Whiskered Anklet). Southern Hemisphere procellariiforms
occur regularly in the offshore waters of the southern Bering Sea and northern
Gulf of Alaska during Alaskan summers. Although breeding diversity of passerines
(mainly Lapland Longspur, Snow Bunting, and Gray-crowned Rosy-Finch), and
shorebirds (e.g., Black Oystercatcher, Dunlin, Ruddy Turnstone, Rock Sandpiper)
is low, numerous Old World species are regular migrants and visitants. Some of
these species regularly breed in the region (e.g., Common Ringed Plover, Wood
Sandpiper, Eurasian Skylark). Rock Sandpipers have differentiated into three
races among islands within the region and the only endemic Alaskan passerine
(McKay’s Bunting) is found here.
Northwestern
Interior
Forest
This region is an
extensive (278,800 square-miles; 722,000 km 2 )
patchwork of ecological types. Sub-regions include: A) Interior Highlands and
Ogilvie Mountains, B) Interior Forested Lowlands and Uplands, Interior
Bottomlands, and Yukon Flats, C) Alaska Range, Wrangell Mountains, and Copper
Plateau, and D) Cook Inlet. In the interior, winters are cold (average minimums
-1 0 F to -31 0 F;
-18 0 C to -35 0 C) and summers
are warm (average maximum 63 0 F
to 72 0 F; 17 0 C to 22 0 C).
The Cook Inlet region has both maritime and continental influences and the
state’s most populous region, two-thirds of Alaska’s population reside here,
enjoys a mild year-round climate. A mosaic of vegetation communities arise from
the interplay of elevation, permafrost, surface water, fire, and aspect. All
forest types (needleleaf, deciduous, and mixed) are found in the region and are
dominated by white spruce, black spruce, poplars, and paper birch. Tall shrub
communities occur along rivers, drainages, and near treeline. Bogs, consisting
of low shrubs and shrub-graminoid communities, are common in the lowlands.
Alpine dwarf scrub communities are common in Interior Highlands and throughout
mountainous regions; highest elevations are generally devoid of vegetation.
Despite the varied ecoregions, many bird species are shared among the regions.
Lowlands, bottomlands and flats harbor many species of migrating and breeding
waterfowl (e.g., Northern Pintail, Northern Shoveler, Green-winged Teal) and
swans. These ecoregions, combined with forested lowlands and uplands support
breeding shorebirds such as Greater and Lesser Yellowlegs, Solitary and Spotted
Sandpipers, and Common Snipe. American Golden-Plovers and Surfbirds are found in
alpine habitats in Interior Highland and mountainous ecoregions. The unvegetated
intertidal area of Cook Inlet has recently been identified, not only as a major
spring stopover site for Western Sandpipers and Dunlins, but also as the primary
wintering site for the nominate form of Rock Sandpiper (C. p. ptilocnemis).
Significant numbers of Long- and Short-billed Dowitchers and Hudsonian Godwits
stop in upper Cook Inlet during migration as do Wrangel Island Snow Geese during
the spring. A suite of passerines inhabit forest, scrub, and graminoid
communities in the region. Black-capped and Boreal Chickadees, Ruby-crowned
Kinglets, Swainson’s Thrushes, Yellow-rumped Warblers and Dark-eyed Juncos are
common forest species. Tall shrub communities host White-crowned, American Tree,
and Fox Sparrows, Wilson’s and Yellow Warblers, Gray-cheeked Thrushes, and
Common Redpolls, among others. At high elevations, Horned Lark and Lapland
Longspur are common breeders.
Northwest Pacific Rainforest - Formerly Southcentral and Southeastern Alaska
The coastal rainforest stretches from extreme southern Alaska to the western Gulf of Alaska and is characterized by heavy precipitation and mild temperatures typical of a maritime climate. Sub-regions include: A) Coastal Hemlock-Spruce Forests, and B) Pacific Coastal Mountains. The regions stark, rugged features are a result of intense glaciation during the Pleistocene and nearly all adjacent land area remains glaciated. Much of the terrain is steep sloped from sea level up to 3,300 feet (1,000 m), but large floodplains, alluvial fans, outwash plains, and river deltas also occur here. The region is dominated by needleleaf forests of Western Hemlock and Sitka Spruce; other needleleaf species also occur in coastal forests. Broadleaf forests are found along large mainland river drainages. Several other communities are present in this region and include: tall, low, and dwarf scrub; tall and low scrub bogs and swamps; and wet graminoid and forb herbaceous communities. The Copper and Stikine River deltas and the Yakutat forelands are major stopover sites for migrating shorebirds, especially Western Sandpipers and Dunlins. Black Oystercatchers, Rock Sandpipers, Black Turnstones, and Surfbirds are common wintering species. Nearshore marine areas support many breeding and wintering sea ducks (e.g. Surf Scoter, Harelquin Duck) and seabirds (e.g., Black-legged Kittiwakes, murres, murrelets). Coastal forests support a host of resident and breeding passerines (e.g., Chestnut-backed Chickadee, Winter Wren, Brown Creeper, Ruby and Golden-crowned Kinglets, Red-breasted Sapsucker), raptors (Bald Eagle, Northern Goshawk, Northern Saw-whet Owl), and seabirds (Marbled Murrelet).
Alaska Biological Science Center