By Dr. Rob Norman
Sunken Island is part of the wonderful Florida Coastal Islands Sanctuaries and one of the two big islands of the Alafia Bank Sanctuary (Bird Island to the east; Sunken Island to the west). Located in Hillsborough Bay at the mouth of the Alafia River, the two man-made islands were formed in the late 1920s from spoil material when a channel that connects the main Tampa shipping channel to the Alafia River was dredged. Bird nesting sites for gulls, terns, and skimmers quickly began to populate the islands. Over time, shrubs and trees replaced low-lying vegetation. Nesting roseate spoonbills, herons, egrets, ibis, and later pelicans moved to the islands from the historic nesting site at Green Key.
We gained access to the beautiful islands in less than a 10 minute boat ride from the dock at Williams Park at US 41. Right away the amazing birds were visible everywhere, strutting their stuff on the beach, calling out from the mangroves and doing amazing aerial acrobatics above us. We photographed reddish egrets (small, rare herons), baby pelicans, roseate spoonbills and a wide variety of other species.
The sanctuary hosts one of the largest bird colonies in Florida and one of the most diverse colonies in the continental United States. Every year up to 18,000 nesting pairs of up to 20 species of birds nest on the Alafia Bank Sanctuary. The Alafia Bank is listed by the Florida Fish & Wildlife Conservation Commission as the most important colony in the state, due to its size (number of birds nesting), longevity of nesting activity, and species diversity.
In 1977, a 12-acre “Alafia Extension” was added to the west end of Sunken Island with material from a nearby dredging project. When you come close, you see the results of the plantings including smooth cordgrass (Spartina alterniflora) and mangroves. Tidal pools, mud flats, and even small creeks and salt barrens cover the island. The islands are owned by the Mosaic Company and leased to Audubon for operation as a sanctuary.
The extension provides safe nesting, feeding, and relaxing habitats for breeding and migratory birds. Most importantly, please know that you are not allowed on the islands because of the fragility of the wildlife and the key importance of this ecosystem. The photos that are shown were taken more than 30 yards from the shore (Yes—it helps to have a good camera and lens!)
Dr. Rob Norman is a dermatologist, writer, photographer, and blues harmonica player. He can be reached at 880-7546.