The Back Bay, as Upper Newport Bay is known locally, is one of the last surviving coastal salt marshes in southern California. It is a major stopping-point on the Pacific Flyway: more than 200 bird species pass through, and you can reliably see herons, egrets, pelicans, terns and the rare Belding's savannah sparrow on a short morning visit.
A 10-mile loop trail circles the bay, almost entirely flat, used by walkers, runners and cyclists. The Peter and Mary Muth Interpretive Center on University Drive has free exhibits on the estuary's wildlife and a panoramic deck over the water. Kayaks can be rented from the boat-launch at Newport Aquatic Center. Avoid the middle of summer days — the mosquitoes can be brutal in the marshes.