There are many places to bird watch on the East Coast, and Cape May, New Jersey may be among the best.
Located at the southernmost tip of the Cape May Peninsula in Cape May County, New Jersey, it is one of the first land masses that birds and butterflies encounter while migrating West, and for that reason alone, the marshes are great places to bird spot.
New Jersey's Audubon Society's Cape May Bird Observatory is located here, and provides guidance and material for professionals and amateurs alike. If you visit in August-September, be prepared for a surprise (you'll likely spot Monarch butterflies, egrets, seagulls and more!).