Puget Trough Ecoregion and Birding Sites

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Click to see a detailed map with birding sites.

Location

This ecoregion embraces the lowlands and marine waters lying between the Cascades on the east and the coastal ranges on the west, from sea level to an elevation of about 1,000 feet, as well as the Strait of Juan de Fuca coastal plain west to the Twin Rivers mouth and the western end of the Columbia Gorge upriver to Cape Horn. Beyond Washington, the ecoregion extends north to include the Georgia Depression of southwestern British Columbia and south through Oregon's Willamette Valley.

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Physiography

The Puget Trough marks the western shore of the former North Cascades microcontinent, which joined the North American continent some 50 million years ago. During the Pleistocene glaciation, ending about 10,000 years ago, the northern part of the ecoregion was deeply excavated by glacial action and depressed by the weight of mile-thick ice sheets, creating the basins and channels now occupied by the salt waters of Puget Sound and by many freshwater lakes. Soils are mostly recent glacial debris, thousands of feet deep in places. South of the Sound, from Tacoma and Olympia to Toledo, glacial outwash deposited large expanses of gravelly, fast-draining soils. Beyond the reach of the last glaciation, the lands still farther south are characterized by older alluvial soils, while the plains around Vancouver are composed of rich, deep silt resulting from repeated ice-age flooding of the Columbia River. Numerous large rivers flow down from the Cascades to Puget Sound, often forming extensive estuaries of which the Skagit, Stillaguamish, Snohomish, and Nisqually are among the least disturbed. The Chehalis River drains the part of the ecoregion immediately south of the Sound toward the Pacific Ocean, while the Cowlitz River and lesser streams drain the ecoregion's southern extremity to the Columbia.

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Climate

The ecoregion enjoys a temperate climate, moderated by maritime influence. Mean temperatures in Seattle and Vancouver are 39-40 degrees F in January, 65-66 degrees F in July. Precipitation is much influenced by the rain-shadow effect of the coastal ranges on the prevailing, moisture-laden southwest winds. Average annual precipitation ranges from 35-50 inches at or near sea level, rises to 60-80 inches in the Cascade foothills, but drops to 15-30 inches in the rain shadow of the high Olympics (northeast Olympic Peninsula, San Juan Islands, Whidbey Island). Precipitation is heaviest in the late-fall and winter months. Most years see one or two short bouts of snow, but usually no more than a few inches fall and do not persist.

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Habitats

The original vegetation consists mostly of conifer-dominated forest of Douglas-fir, western hemlock, western red cedar, western white pine, and bigleaf maple. Typical understory plants include sword fern, salal, salmonberry, Cascade Oregon grape, snowberry, evergreen huckleberry, red elderberry, ocean spray, and vine maple. Red alder pioneers after fires or other disturbances. Madrone appears frequently in drier places and on coastal bluffs, and other heathers such as rhododendron and manzanita dominate areas with poor soil. Sites within the Olympic rain shadow and on fast-draining soils south of Puget Sound support prairies and dry forests of Douglas-fir, Garry oak, and lodgepole pine. Willows, bigleaf maple, red alder, and black cottonwood dominate the ecoregion's riparian corridors and ring the many freshwater lakes, ponds, and marshes. Garry oak and Oregon ash become increasingly common farther south-e.g., on the Columbia River floodplain. Marine habitats include open water, brackish estuaries, salt marshes, tidal flats, and sandy and rocky shorelines, the latter found only in the northern part. Oceanic influence-strong on the broad, deep Strait of Juan de Fuca-diminishes progressively as one moves farther inland to the comparatively shallow, protected waters of the South Sound.

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Human Impact

The Puget Trough Ecoregion is a highly fragmented landscape. Over 70 percent of Washington's human population lives here, occupying just eight percent of the land area of the state. In addition, it is the state's busiest transportation corridor, both land and water. Much of the original vegetation has been obliterated by land clearing, agriculture, logging, road-building, and settlement. Dikes, dams, dredging, draining, filling, and reinforcement of stream banks and shorelines have greatly altered the natural hydrology. Almost no old-growth conifer forest survives; the remnants are in tiny patches. Fire suppression, snag removal, clear-cutting, and other industrial forestry practices have altered the natural succession of the still-forested landscape, leading to a monoculture of even-aged tree stands with low avian diversity. Over 95 percent of the prairies of the South Sound have given way to farming and suburban sprawl. Fire suppression has encouraged native trees and exotic plants to colonize what remains of this distinctive landscape.

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Abundance Code DefinitionsBird Checklist

C=Common; F=Fairly Common; U=Uncommon; R=Rare; I=Irregular
BirdJanFebMarAprMayJunJulAugSepOctNovDec
Greater White-fronted GooseUUUFU UFFUU
Snow GooseCCCCU RCCC
Ross's GooseRRRR RR
BrantCFFCURRRRFCC
Cackling GooseCCCCU UCCC
Canada GooseCCCCCCCCCCCC
Trumpeter SwanCCFU RCC
Tundra SwanCCCU UCC
Wood DuckUUFFCFFFFUUU
GadwallCCCCCCCCCCCC
Eurasian WigeonUUUUR RUUU
American WigeonCCCCURRUCCCC
MallardCCCCCCCCCCCC
Blue-winged Teal RFFUUR
Cinnamon TealRRRFFFFFURRR
Northern ShovelerCCCCCFFFCCCC
Northern PintailCCCCURRUCCCC
Green-winged TealCCCCFRRFCCCC
CanvasbackFFUUR RUCF
RedheadRRRRRRRRRRRR
Ring-necked DuckCCCFFUUUUFCC
Greater ScaupCCCFF UFCC
Lesser ScaupCCCCUUUUUFCC
Harlequin DuckFFFUUUFFFFFF
Surf ScoterCCCCCFFFFCCC
White-winged ScoterCCCCCFUUFFCC
Black ScoterUUUUU RRUUUU
Long-tailed DuckCCCUU FCC
BuffleheadCCCCCRRRUCCC
Common GoldeneyeCCCFU RRUCC
Barrow's GoldeneyeCCCCRRRRRUCC
Hooded MerganserFFCFFFFFFFCC
Common MerganserCCCCCCCCCCCC
Red-breasted MerganserCCCCURRRUFCC
Ruddy DuckCCCCFUUUUFCC
Ring-necked PheasantFFFFFFFFFFFF
Ruffed GrouseUUUUUUUUUUUU
Sooty GrouseUUUUUUUUUUUU
Wild TurkeyRRRRRRRRRRRR
Mountain QuailRRRRURRURRRR
California QuailFFFFFFFFFFFF
Northern BobwhiteRRRRRRRRRRRU
Red-throated LoonCCCCFRRRCCCC
Pacific LoonCCCCCRRRFCCC
Common LoonCCCCCFFFCCCC
Yellow-billed LoonRRRR RRRRR
Pied-billed GrebeCCCCCCCCCCCC
Horned GrebeCCCCR RFCCC
Red-necked GrebeCCCFU RFFCCC
Eared GrebeUUUUR UUUU
Western GrebeCCCCURUUFCCC
Clark's GrebeRRRR RRR
Northern FulmarRRRRRRRRRRRR
Short-tailed Shearwater RR
American White PelicanRRRRRRRRRRRR
Brown Pelican RRRR
Brandt's CormorantCCCCCCCCCCCC
Double-crested CormorantCCCCCCCCCCCC
Pelagic CormorantCCCCCCCCCCCC
American BitternUUUUUUUUUUUU
Great Blue HeronCCCCCCCCCCCC
Great EgretUUUUUUFFFFFF
Cattle EgretR RRR
Green HeronRRRUFFFFFURR
Black-crowned Night-HeronRRRRRRRRRRRR
Turkey Vulture RUFFFFFCFR
Osprey RFFFFFFUR
White-tailed KiteUUUURRRUUUUU
Bald EagleCCCCCCCFFFCC
Northern HarrierFFFFUUUUFFFF
Sharp-shinned HawkUUUFUUUUFFUU
Cooper's HawkUUUUUUUFFFUU
Northern GoshawkRRRRRRRRRRRR
Red-shouldered HawkRRR RRRRR
Red-tailed HawkCCCCCCCCCCCC
Rough-legged HawkFFFU RUFF
Golden EagleRRRRRRRRRRRR
American KestrelUUUUUUUUUUUU
MerlinUUUUURRUUUUU
GyrfalconRRR RR
Peregrine FalconUUUUUUUUFFUU
Prairie FalconRRR RR
Virginia RailFFFFFFFFFFFF
SoraRRRUUUUUUURR
American CootCCCCFFFFCCCC
Sandhill CraneFFFUR UFFF
Black-bellied PloverFFFFURRCCFFF
American Golden-Plover RR
Pacific Golden-Plover RRR
Semipalmated Plover UF FFFR
KilldeerCCCCCCCCCCCC
Black OystercatcherUUUUUUUUUUUU
Black-necked Stilt RRR
Spotted SandpiperRRUUFFFFFUUR
Solitary Sandpiper UU RUU
Greater YellowlegsUUUCFRUCCFFU
Lesser Yellowlegs UU RFFR
Whimbrel UU RUUR
Marbled GodwitRRRR RRRRRR
Ruddy TurnstoneRRRUU UURRRR
Black TurnstoneCCCCU UUFCCC
SurfbirdFFFFR RUUFFF
Red Knot R RRR
SanderlingCCCFU RUCCCC
Semipalmated Sandpiper R UUR
Western SandpiperUUUCCRCCCFUU
Least SandpiperUUUCCRCCCUUU
Baird's Sandpiper RR
Pectoral Sandpiper RR RUFU
Sharp-tailed Sandpiper RR
Rock SandpiperRRRR RRR
DunlinCCCCF RRRCCC
Stilt Sandpiper RR
Ruff RRR
Short-billed Dowitcher FFRFFUR
Long-billed DowitcherUUUFF FFFFFU
Wilson's SnipeUUFFUUUUFFFU
Wilson's Phalarope RRRR
Red-necked Phalarope RF RCFR
Franklin's Gull RRRR
Little GullR RR RRR
Bonaparte's GullCCCCF RFCCCC
Heermann's GullR UFFFUR
Mew GullCCCCU RUCCCC
Ring-billed GullCCCCCCCCCCCC
California GullRRRUUFCCCCFR
Herring GullUUUUR RUUUU
Thayer's GullFFFUR RUUF
Western GullUUUUUUUUUUUU
Glaucous-winged GullCCCCCCCCCCCC
Glaucous GullRRR RR
Caspian Tern RCCCCCFR
Black Tern RRRR
Common Tern R RFCU
Arctic Tern RRRR
Parasitic Jaeger RUFUR
Common MurreCCCCCCCCCCCC
Pigeon GuillemotCCCCCCCCCCCC
Marbled MurreletFFFFFFFFFFFF
Ancient MurreletUUU UFF
Rhinoceros AukletFFFCCCCCFFFF
Tufted Puffin UUUUU
Rock PigeonCCCCCCCCCCCC
Band-tailed PigeonUUFFFFFFFUUU
Mourning DoveFFFFFFFFFFFF
Barn OwlUUUUUUUUUUUU
Western Screech-OwlUUUUUUUUUUUU
Great Horned OwlFFFFFFFFFFFF
Snowy OwlIIII II
Northern Pygmy-OwlUUUUUUUUUUUU
Spotted OwlRRRRRRRRRRRR
Barred OwlFFFFFFFFFFFF
Great Gray OwlIII I
Long-eared OwlRRRRRRRRRRRR
Short-eared OwlFFFRR RFFF
Northern Saw-whet OwlUUUUUUUUUUUU
Common Nighthawk UUUR
Black Swift UUUUU
Vaux's Swift UFFFCCR
Anna's HummingbirdCCCCCCCCCCCC
Calliope Hummingbird RR
Rufous Hummingbird RUCCCCFF
Belted KingfisherFFFFFFFFFFFF
Red-naped Sapsucker R
Red-breasted SapsuckerFFFFFFFFFFFF
Downy WoodpeckerFFFFFFFFFFFF
Hairy WoodpeckerFFFFFFFFFFFF
Northern FlickerCCCCCCCCCCCC
Pileated WoodpeckerFFFFFFFFFFFF
Olive-sided Flycatcher RUFFFR
Western Wood-Pewee UFFFU
Willow Flycatcher UCCCU
Hammond's Flycatcher UFUUFF
Dusky Flycatcher R
Pacific-slope Flycatcher UCCCFU
Say's Phoebe RR
Western Kingbird RRRR
Eastern Kingbird RRRR
Northern ShrikeUUUR UUU
Cassin's Vireo RFFFFU
Hutton's VireoFFFFFFFFFFFF
Warbling Vireo UCCCCF
Red-eyed Vireo RFFUU
Gray JayUUUUUUUUUUUU
Steller's JayCCCCCCCCCCCC
Western Scrub-JayCCCCCCCCCCCC
American CrowCCCCCCCCCCCC
Northwestern CrowCCCCCCCCCCCC
Common RavenFFFFFFFFFFFF
Horned LarkRRRRRRRRRRRR
Purple Martin UFFFFR
Tree SwallowRUCCCCFUR
Violet-green Swallow UCCCCCFR
Northern Rough-winged Swallow UFFFFU
Bank Swallow RUUUUR
Cliff Swallow RUCCCCR
Barn SwallowRRRUCCCCFUR
Black-capped ChickadeeCCCCCCCCCCCC
Chestnut-backed ChickadeeCCCCCCCCCCCC
BushtitCCCCCCCCCCCC
Red-breasted NuthatchCCCCCCCCCCCC
White-breasted NuthatchUUUUUUUUUUUU
Brown CreeperFFFFFFFFFFFF
Bewick's WrenCCCCCCCCCCCC
House Wren RFFFR
Pacific WrenCCCCCCCCCCCC
Marsh WrenFFFCCCCCCCFF
American DipperUUUUUUUUUUUU
Golden-crowned KingletCCCCCCCCCCCC
Ruby-crowned KingletCCCCU RCCCC
Western BluebirdRRUUUUUUURRR
Townsend's SolitaireRRRUR RRR
Swainson's Thrush FCCCFR
Hermit ThrushUUUFU UFUU
American RobinCCCCCCCCCCCC
Varied ThrushCCCCUUUUFCCC
European StarlingCCCCCCCCCCCC
American PipitUUUFU UCFUU
Bohemian WaxwingIII I
Cedar WaxwingRRRUCCCCCCUR
Orange-crowned WarblerRRUFCCCCCUUR
Nashville Warbler RR R
Yellow Warbler RCCCCCR
Yellow-rumped WarblerUUUCCFFFFCFU
Black-throated Gray Warbler UCCCCCR
Townsend's WarblerUUUCCCCCCUUU
Hermit Warbler UUUUR
MacGillivray's Warbler UCCCCU
Common YellowthroatRRRFCCCCCRRR
Wilson's Warbler FCCCCFR
Yellow-breasted Chat RR
Western Tanager RCCCCFR
Spotted TowheeCCCCCCCCCCCC
American Tree SparrowRR RRR
Chipping Sparrow FFFFU
Vesper Sparrow RRRRRRR
Savannah SparrowUUUCCCCCCFUU
Fox SparrowCCCCFRRRFCCC
Song SparrowCCCCCCCCCCCC
Lincoln's SparrowFFFFR RFFFF
Swamp SparrowRRR RR
White-throated SparrowUUUUR RUUU
Harris's SparrowRRRR RR
White-crowned SparrowFFCCCCCCCCFF
Golden-crowned SparrowCCCCF FCCC
Dark-eyed JuncoCCCCCCCCCCCC
Lapland Longspur RRR
Snow BuntingRR RR
Black-headed Grosbeak RCCCCF
Lazuli Bunting UUUR
Red-winged BlackbirdCCCCCCCCCCCC
Western MeadowlarkUUUUURRRRUUU
Yellow-headed Blackbird RUUURRR
Rusty BlackbirdRR RRR
Brewer's BlackbirdCCCCCCCCCCCC
Brown-headed CowbirdUUUCCCCFFFUU
Bullock's Oriole FFFR
Purple FinchFFFFFFFFFFFF
House FinchCCCCCCCCCCCC
Red CrossbillFFFFFFFFFFFF
Common RedpollIII II
Pine SiskinCCCCCCCCCCCC
American GoldfinchUUUCCCCCCCUU
Evening GrosbeakFFFFFFFFFFFF
House SparrowCCCCCCCCCCCC

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