 Thousands of migratory birds visit the refuge during their annual north–south flights.As of 2010, more than 185 bird species have been recorded in the refuge including herons, egrets, hawks, osprey, shorebirds, gulls, terns, hummingbirds, woodpeckers, grebes, falcons, vultures, waterfowl, and many others.Vegetation, which varies from one part of the refuge to another, includes Oregon white oak, Pacific madrone, ash, and black locust trees; ferns, Oregon-grape, Scotch broom, and poison oak, as well as rushes, sedges, and other plants.