About half an hour north of Vancouver [1], nature lovers will have ample opportunity to explore fields, woodlands, and wetlands at Ridgefield National Wildlife Refuge (360/887-4106), which fans over 5,150 acres around the marshy lower Columbia River. Bring your binoculars in winter, when up to 10,000 geese and 40,000 ducks land here.
Hiking and fishing are permitted—the two-mile Oaks to Wetlands Wildlife Trail is popular with all ages. Parts of the refuge are closed October–mid-April.
Links:
[1] http://www.moon.com/destinations/washington/columbia-gorge-and-wine-country/vancouver