Bottle Beach State Park is a 75-acre day-use park with 6,000-feet of shoreline on Grays Harbor. The open tide flats are the park's most significant feature. Mud flats in the area support a rich supply of invertebrates that attract shorebirds as they migrate from Central and South America to their breeding grounds in the Arctic. Grays Harbor is considered the single most important shorebird feeding area on the Pacific Coast, attracting more than a million birds each spring.

Up to 20% of these migrating birds use the area just off Bottle Beach, which has been designated an Important Bird Area by the Audubon Society. Large numbers of migratory waterfowl also use the area. Raptors such as peregrine falcons visit the area because of the abundant prey available. In all, more than 130 species of birds have been observed at Bottle Beach.