For birders seeking deep water diving birds or shorebirds, it is best to visit the Refuge within two hours of high tide.  The food for these birds follows the shoreline, so at high tide there will be an abundance of birds pushed inland up along the Estuary Trail dike.  Diving birds, as well as seals and jellyfish, will be visible under the Estuary Trail boardwalk.  Here are tide charts for 2013: