IBA of the Month: Government Island

One of four Important Bird Areas in the Portland metropolitan region, Government Island State Park represents over 2,000 acres of unique urban green space. This vital open space hosts both resident and migratory birds that live in or visit our urban environment.  Located in the Columbia River just northeast of the Portland International Airport (PDX) airfield, it is actually a small archipelago of islands accessible only by boat or an adrenaline-driven canoe trip.  The islands represent a variety of wildlife habitats including Pacific Willow, Oregon Ash and Black Cottonwood stands interspersed among meadow grasslands, ponds and lakes; together these support a robust array of wildlife including 80 avian species, 2 herptile species, and 8 mammal species amidst Portland’s most industrialized corridor!  Government, Lemon and McGuire Islands are predominantly owned by the Port (Metro owns a 224-acre section), but are managed by Oregon State Parks for wildlife habitat, cattle grazing, and passive recreational opportunities.

Envisioned for development into expanded airfield space when the Port bought it in 1969, Government Island got a new lease on life when airport development intentions were halted.  Once visited by Lewis and Clark, farmed by the US Government, and hunted by European fur traders, Government Island is now used in part as a Port mitigation site, is leased in part to a cattle rancher, and in part offers passive recreation opportunities to the public on perimeter beaches.  

Jewit Lake and West Pond mitigation sites on Government Island were mandated to offset loss of wetlands resulting from 65 acres of filled wetland in the SW Quadrant of PDX.  The site encompasses 450 acres of emergent and forested wetlands, and uplands, fenced to exclude cattle.  A fish-exclusion structure installed in 1993 prevents salmonid species from entering the lake, per National Marine Fisheries Service.  Invasive plant removal including himalayan blackberry, tansy ragwort, and reed canarygrass are part of the island’s habitat restoration program. Weed control efforts by the Port and Oregon Department of Agriculture include mowing, herbicide application, and biological controls.  Required monitoring on the mitigation site was performed by Portland State University students for the first five years, and now continues on a monthly basis by Port property management staff.

Shad, smelt, and sturgeon use the south channel of the Columbia along Government Island for both feeding and passage.  This relatively protected channel is characterized by sandy beaches with a water depth of less than 10 feet, depending on tidal cycle and river stage.  The considerably deeper north shore navigation channel occasionally hosts Salmon, Steelhead and Sturgeon.

A diverse array of bird species utilize Government Island, including Bald Eagle, Peregrine Falcon, Pileated Woodpecker, Willow Flycatcher, Olive-Sided Flycatcher, Western Meadowlark, Horned Grebe, Red-necked Grebe, Bufflehead, and Purple Martin according to a 1993 PSU study. The island has historically hosted a Great Blue Heron rookery, which peaked at 94 nests as recently as two years ago.  Heron are attracted to the plentiful prey base, including meadow voles and fish in shallows of Jewit Lake. Nest trees eroding out along the edges of the island have led to a rookery shift in recent years.  Nests on Government Island have dwindled, but with a concurrent rise on both McGuire and Tri-Club Island, as well as Reed Island to the east (where nest counts have risen to 73).

Migratory waterfowl congregate in emergent wetlands, seasonal ponds and upland meadows on the islands.  Pied-billed Grebe, American Widgeon, Cinnamon Teal, Green-winged Teal, Mallard, Pintail, Northern Shoveler, and Canada Goose are all common species.  Other species found on Government Island include American Crow, California Gull, Green Heron and Hooded Merganser, with seasonal wetlands and grasslands attracting Killdeer, Greater Yellowlegs, Dowitchers and Wilson’s Snipe.  Raptor presence includes Red-tailed Hawk, Northern Harrier, Cooper’s Hawk, Great Horned Owl, Merlin, American Kestrel, and Peregrine Falcon.

Two docks and a floating tie-up on the north side of the island will welcome your arrival by boat.  Restrooms are located on Government, Lemon and McGuire Islands, and overnight camping is permitted below ordinary high water (the vegetation line) around the perimeter beaches and in limited upland areas where picnic tables have been provided for visitors.  Hunting is allowed only below ordinary high water to minimize flushing birds toward the airfield, and interior access is accessible only by permit.  Trails along the north sides of Lemon and Government Islands facilitate day hikes where access is allowed.   

If you’d like to get involved in future monitoring of bird species on this IBA, call Mary Coolidge at 503.292.6855 x111 or email mcoolidge@audubonportland.org to find out about our upcoming Bird Monitoring Training, a two-day course open to intermediate birders who want to help conduct citizen science projects on Important Bird Areas!