Dry Tortugas Apr 27—30, 2011
Posted by Michael O'Brien
We had a splendid visit to the Dry Tortugas this spring. Our boat, the Playmate, was small but very comfortable, and the crew was friendly and accommodating. On our voyage out to the Tortugas, we swung south just enough to pass through the Gulf Stream where we found a number of interesting offshore species, including Audubon's Shearwater, Northern Gannet, Bridled Tern, Pomarine Jaeger, and our first Masked Booby, Sooty Terns, and Magnificent Frigatebirds. As we got closer to the Tortugas, investigation of various buoys and markers yielded excellent views of Brown Booby and Roseate Tern, as well as our first looks at Brown Noddy. And a swing by Hospital Key got us fairly close to the growing colony of Masked Boobies there (up to 70 birds, at least).
While at the Tortugas, we spent the majority of our time exploring Fort Jefferson on Garden Key. This is the most vegetated island, and the only one with fresh water (a modified water fountain) so it is a real magnet for migratory birds. We saw swallows, vireos, thrushes, grosbeaks, and buntings, but warblers were the real highlight. We found 18 species of warblers there on our short visit, many of them offering very close views. One particular Worm-eating Warbler seemed to walk right up to us as it foraged on the ground. And a male American Redstart did just about the same thing. Numbers of individuals were not high, but the diversity was excellent and it seemed like every tree had something moving.
One of the more frustrating, but still exciting events was our nighthawk experience. We had leisurely studies of a pair foraging around Fort Jefferson one late afternoon. All visual characteristics pointed to them being Antillean Nighthawks (which would have been a life bird for many in the group), but alas, they did not vocalize to confirm their identification. It was interesting though. It was also interesting to notice species just passing over the Tortugas without stopping. Shorebirds, in particular, were often flying over, dropping down just low enough for us to detect them calling overhead. Of course some shorebirds did stop, and we particularly enjoyed nice studies of a White-rumped Sandpiper on the beach. And the award for most out of place bird went to the Sora, which flushed out of a tree and then headed up to the brick walls of Fort Jefferson, investigating crevices to hide in. We all hoped it found its way to a peaceful cattail marsh somewhere.
What was no doubt most memorable about the Dry Tortugas was the seabird colony. Upon arriving at the Tortugas, it is difficult not to feel like one has been transported to another world. The seething mass of Sooty Terns and Brown Noddies is absolutely mesmerizing, and they were always there! Whether we were taking dinghy rides right by the colony, or walking around Fort Jefferson, or anchored for the night and watching the sun set from on deck, the terns were flying, calling, chasing one another, chasing intruding Peregrines, and skimming the water to drink. They never stopped. Amazing! And having an abundance of Magnificent Frigatebirds constantly sailing overhead, occasionally with pouches inflated, was also a treat and added to the unique ambiance of this special place.