Tualatin River National Wildlife Refuge - Natural Environment

Natural Environment

Before becoming a protected area, much of the land in the Tualatin River National Wildlife Refuge was agricultural, with hog and dairy farms, and crops such as corn (maize) and onions. Today, the refuge spreads out over ten miles (16 km) along the Tualatin River, Rock Creek, and Chicken Creek, and is managed in five main sections (units): Rock Creek, Onion Flats, Riverboat, Tualatin River, and Atfálat´i.

The refuge also includes the Tonquin scablands created by the Missoula Floods to the southeast of the river. These scablands were scoured of the top layers of soil, leaving a marsh-filled valley. There is also the Wapato Lake Unit approximately 15 miles (24 km) to the west. Located along the Pacific Flyway for migratory birds, this shabitat includes seasonal wetlands, streams, forested wetlands, savanna, riparian zones, forested uplands, and the Tualatin River and portions of its floodplain.

The refuge is home to almost 200 species of birds, more than 50 mammal species, and 25 species of reptiles and amphibians. Tree species include red alder, aspen, maple, oak, Oregon white ash, Douglas fir, ponderosa pine, Pacific yew, and cedar. A pair of 350 year-old oak trees can be found at the visitor center. Plant species in the refuge include bulrushes, wapato, water plantain, as Oregon grape, wild trillium, camas, iris, snowberry, cattails, wild millet, wild rose, thimbleberry, and others. Wildflowers include Blue chicory, Douglas spirea, and purple crocuses.

Waterfowl at the refuge are great blue herons, Canada geese, wood ducks, swans, Northern Pintails, green herons, teals, mergansers, belted kingfishers, and American wigeons among others. Birds that spend time there include, sandhill cranes, Oregon juncos, wren, common starlings, blackbirds, nuthatches, Pacific-slope flycatchers, red-tailed hawks, American goldfinch, peregrine falcons, Yellow warblers, Western flycatchers, killdeer, northern harriers, osprey, egrets, quail, pheasants, golden-crowned kinglets, owls, and Black-headed Grosbeaks to name a few. There is also a pair of bald eagles. The year it was created officials counted 24 different bird species. By 2008 there were 185 birds species represented at the refuge.

River otter, beaver, nutria, mink, weasel, red fox, deer, elk, coyotes, raccoons, and rabbits make up a portion of the terrestrial animals. Other wildlife includes painted turtles, frogs, salamanders, crawfish, fish, and alligator lizards. The refuge is one of only ten national wildlife refuges in the United States located in an urban area. Groups have suggested that the refuge be expanded all the way to the Willamette River to provide a greenway through a heavily populated area. The Tualatin's floodplain is the largest of any of the Willamette River’s tributaries.