Birders on safari Aug. 21 at the Ridgefield National Wildlife Refuge in Ridgefield, Wash. (Photo by Matthew Ginn © 2010)

About a 18 months ago, Perrie and I visited the Ridgefield National Wildlife Refuge for the first time. Located on the Columbia River, the refuge preserves about 5,300 acres of marsh, grasslands and woodlands as natural habitat for birds, fish, and other wildlife, and is largely off-limits to the public.

Our first visit was to the northern ‘Carty’ unit of the refuge (map); this time we visited the central ‘S’ unit. (The Bachelor Island, Roth, and Ridgeport Dairy units are closed to the public.)

The distinctive feature of the ‘S’ unit is its 4.2-mile auto tour route. We thought that seemed silly, so we walked along the gravel road. But there were plenty of people on safari. We also walked the 1.5-mile Kiwa trail that loops off the auto route at about the halfway mark.

Not surprisingly, there was plenty of wildlife to see: turtles, frogs, and a water snake in one swamp. A great blue heron on the hunt, scattering the frogs in another. American coots, mallards, and other ducks. Egrets, green heron, sandpipers, killdeer, a hermit warbler, and more. And in every marsh, beaver-like rodents known as nutria (or coypu).