Dry Tortugas Apr 21—24, 2014

Posted by Michael O'Brien

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Michael O'Brien

Michael O'Brien is a freelance artist, author, and environmental consultant living in Cape May, New Jersey. He has a passionate interest in bird vocalizations and field ide...

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The Dry Tortugas have long been on the short list of “must see” destinations for birders in North America. And it’s easy to see why. A trip to the Tortugas combines a taste of tropical pelagic birding, the excitement of a migrant trap where you never know what colorful avian jewels await you, and the mesmerizing abundance of a thriving seabird colony, including several species that are rarely seen elsewhere in the United States. Such a recipe means that any trip to the Tortugas is likely to be a good one, and we were certainly not disappointed.

Masked Booby

Masked Booby— Photo: Michael O’Brien

Departing from Key West, we sailed aboard the M/V Playmate, a comfortable 60-foot vessel run by a highly accomplished crew. En route to the Dry Tortugas, we swung south into deeper water and the Florida Current, which feeds warm Gulf of Mexico water into the Gulf Stream. With diligent scanning, we managed to turn up several distant Audubon’s Shearwaters, as well as quite a few Bridled Terns, some of which provided excellent views. A stop by several offshore markers yielded our first Brown Boobies, while a sprinkling of Magnificent Frigatebirds were seen during the crossing. Upon our arrival at the Tortugas, our first stop was Hospital Key where we enjoyed the ever-increasing colony of Masked Boobies—at least 85 birds were visible!

Indigo Bunting, Hooded Warbler, and Palm Warbler

Indigo Bunting, Hooded Warbler, and Palm Warbler— Photo: Michael O’Brien

We spent one full day and parts of two others exploring Fort Jefferson on Garden Key. Being the most vegetated island, this is where most of the songbird migrants end up. We made repeated forays around the grounds, checking every tree and bush, and scanning the coaling docks from the top of the fort. We usually ended up by the water fountain—the only source of fresh water on the Tortugas and a real magnet for migrants. Although we didn’t see a fallout, the level of migration during our visit was quite good, and we ended up with an impressive list of birds, from shorebirds and raptors to swallows, thrushes, vireos, tanagers, grosbeaks, and orioles. The highlights, of course, were the warblers. We saw 20 species, including such brilliant gems as Blue-winged, Hooded, Cape May, Magnolia, Yellow-throated, and Black-throated Green. The birdbath was awash with color at times! Probably everyone’s favorite, however, was the comparatively drab Swainson’s Warbler, which allowed particularly good views for such a skulking species. As we roamed the fort, our sharp-eyed group also managed to spot several roosting nighthawks, including both Common and Antillean—an excellent opportunity for study!

Sooty Terns and Brown Noddies, Bush Key

Sooty Terns and Brown Noddies, Bush Key— Photo: Michael O’Brien

Of course, what the Dry Tortugas are most famous for is the seabird colony. Upon arrival at the Tortugas, it was impossible not to be captivated by the seething mass of birds that inhabit Bush and Long keys. Even from a great distance we could see dozens of Magnificent Frigatebirds “kiting” over Long Key, riding the updraft from a steady southerly wind. And when we got a little closer, it was clear that the real show was over Bush Key where some 30,000+ pairs of Sooty Terns and 4,000+ pairs of Brown Noddies make this little island appear to be enshrouded by a swarm of mosquitos. The “wide-awake” calls from Sooty Terns were constant, day and night. A careful eye on the flow of birds revealed nonstop “traffic,” with steady streams of birds heading off to feed while other birds were coming in. In order to get an up-close view of this colony, we took dinghy rides along the marked perimeter. Terns were flying all around us, and would regularly skim the water to drink (they drink seawater and excrete a highly saline fluid from their salt glands). Brown Noddies were often perched on floating structures, allowing extremely close approach, while Sooties perched only on the island. The frigatebirds put on a great show too. Although most of the young were nearly full-sized, several males were still showing their inflated red throat pouches. The incredible sights and sounds of this colony will stay with us all for a long time!

A big thanks goes out to Captain Joe, first mate Adam, and chef Jenny. They kept us safe, comfortable, and well-fed throughout the trip.