On shore enjoy a visit to Joppa Flats, Plum Island and the Parker River National Wildlife Refuge, a popular destination for birdwatchers. Stroll along Newburyport’s riverfront boardwalk or head up High Street to see the old Captain’s homes built in the early 19th century.         Newburyport offers numerous events throughout the summer, including the Riverfront Music Festival and Yankee Homecoming, a week long celebration of New England’s heritage. For information on these and other events call the Newburyport Chamber of Commerce, 978-462-6680, or visit their website.         The Firehouse Center for the Performing and Visual Arts, 978-462-7336, features concerts, plays and two art galleries.         Visit the Custom House Maritime Museum's nautical history exhibits, 978-462-8681.         Walking tours are available from the Tourist Info kiosk, 978-463-6614, at the edge of Waterfront Park.