A good place to start is Smelt Sands Wayside and Yachats 804 Trail. It is usually not crowded and has good beach access. Look for shorebirds and some pelicans from the 3/4 mile trail that is wheelchair accessible.
At Yachats State Park Tidepools, look for oystercatchers and turnstones, also look for the gulls lined up on the fencing.
From the North Access to Yachats Ocean Drive, look for oystercatchers, turnstones, surfbirds, and flocks of sandpipers. The drive has several places to stop.
Visit the Cape Perpetua Visitor Center and check about recent bird sightings.