Dry Tortugas National Park

Curving southwest from land like a string of green-and-sand jewels, the Florida Keys stretch for nearly 180 miles across the limitless blue of the Gulf of Mexico. Most remote of all are the Dry Tortugas, a cluster of waterless islands that rise above dazzling coral reefs, where seabirds swarm like noisy insects and history lingers in the sunbaked walls of a mammoth fort.

In 1513 the Spaniard Juan Ponce do León found the seven tiny islands and named them las Tortugas, "the Turtles," after "the great amount of turtles which there do breed." His crew captured many of the loggerhead, hawksbill, and green sea turtles for their flesh, but they found no fresh water; in later years, maps showed the archipelago as the Dry Tortugas.

Remote as they are, the Dry Tortugas have gone through many incarnations over the years, they have been a pirates' hideaway in the 17th and 18th centuries, a lighthouse, fort, and prison in the 19th century, and a wildlife refuge, historical monument, and finally a national park in the 20th. Today's Dry Tortugas National Park encompasses nearly 100 square miles of ocean but less than 40 acres of day land, a fitting ration, as the natural wonders of this secluded park are largely hidden beneath the waves.

Almost 70 miles west of Key West and even farther from the mainland, the park is accessible only by boat or seaplane. Visitors must rely wholly on themselves, carrying their own shelter, food, and drinking water. But the islands' splendid isolation is also one of their most powerful lures. Gaudy sunsets give way to nights that glow with vivid stars, undimmed by any artificial light; all day the flat horizon marks the unbroken seam between blue sky and azure water, where the only sound is the sea breeze and the shrieks of nesting terns.

Swarms of "Sea Swallows"
In 1825, just four years after Florida became part of the United States, a lighthouse was built on Garden Key, to alert ships to the treacherous shoals and reefs. Despite such warnings, hundreds of vessels wend down in these waters over the years. In 1832 John James Audubon, drawn by the immense numbers of sooty terns and black noddy terns that crowded the low, salt-tolerant shrubs on the keys, sailed to the islands on a federal cutter. His pilot, describing the birds as black and white sea swallows, assured Audubon that "before we cast anchor, you will see them rise in swarms like those of bees when disturbed at their hive, and their cries will deafen you."

Audubon was there to paint birds; others came to profit from them. During his visit, Audubon noticed that commercial collectors were shipping tons of tern eggs to Cuba; even his own shipmates joined in the carnage, and everyone, Audubon included, feasted daily on "delicious" tern eggs.

Nearly a century of protection has allowed the vast breeding colony to regain its former proportions. On tiny Bush Key, more than 100,000 sooty terns jockey for position, dapper in their black-and-white plumage, long wings folded over their deeply forked tails. Pairs of birds scrape a shallow depression in the sand, into which the female lays a single egg, carefully shielding it from the grueling sun. Each night, when darkness protects them from predatory frigate birds, the parents change places at the nest. The colony never really sleeps; at all hours the air above the key seethes with terns, and the night is filled with the racket of their wacky-wack calls.