This place should be on every birder's bucket list. Camp there for a few days, if you can. Make it a day trip if you can't. It's not the easiest place to visit, but by all means try. The park itself is a collection of seven small islands about 70 miles west of Key West (the address above is actually Everglades National Park, which oversees Dry Tortugas). You get there by air or by boat. The Yankee Freedom ferry makes the trip once a day; seaplanes fly in several times a day.
Garden Key is the hub of the park, the site of Fort Jefferson, the Civil War era bastion that guarded the entrance to the Gulf of Mexico. Its strategic location also makes it a magnet for migratory birds as they make their way to places north and south. The list of species that use the islands as a pit stop numbers into the hundreds. The number of species recorded in the park sits at 299. Some breed here, including the magnificent frigatebird, brown noddy and sooty tern. At times, hundreds of noddies and terns can be seen buzzing neighboring Bush Key. Sea turtles nest on Loggerhead Key and some of the outer islands, and there is a resident crocodile. And there is magnificent coral in the shallow, blue waters just offshore.
Camping is considered primative. There are picnic tables and grills available, but you must bring your own food and water. The park's toilets are of the chemical variety; the facilities on the Yankee Freedom may be used when it is docked. The boat also has showers, although using soap is not allowed.
There is an entrance fee to the park and a fee for camping. Check the park website (above) for details. Only Garden and Loggerhead are open to the public year round. Bush opens only for a few months in late fall and early winter. Note: Getting to the park by boat is the only way to camp, either your own or the Yankee Freedom. Make reservations as far in advance as possible to ensure getting the dates you want. Info on getting there by seaplane is here.