Whidbey and Camano Islands are a great place to see birds, with some of the best locations around. The island are along the Pacific Flyway, a western "highway in the sky" birds use to migrate.
Two of the people most knowledgable about bird watching here are Craig and Joy Johnston. The artist/writer couple of produced many amazing photographs of birds and collaborated on several books about birds around here.
They've created a detailed map of the best places to watch birds on Whidbey Island. You can pick up a copy at Island visitor centers.
Or you can see the map here. It has a clickable list of the best places to watch birds on Whidbey Island.