Dry Tortugas Apr 27—30, 2016

Posted by Rafael Galvez

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Rafael Galvez

Rafael Galvez has been birding and illustrating birds since childhood, a dual passion that developed when his family moved from Peru to South Florida. Always with a sketchp...

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With the right combination of planning, weather, and luck, nature-enthusiasts visiting the Dry Tortugas during late April could see large numbers and diversity of songbirds that use the islands of the archipelago as stopover sites during their long migratory journeys. The Dry Tortugas, as the name suggests, have no natural freshwater source. There is limited vegetation on the islands to offer migrants shelter and food. When adverse weather intercepts birds during their nocturnal voyages as they are crossing the Gulf of Mexico towards the U.S. mainland, migrants may drop down on the islands to refuel as the weather improves. The possibility of witnessing a significant migration event is an attracting factor to the Tortugas. However, that is only part of the story. The Dry Tortugas also host important bird colonies for species that nest nowhere else on the continent, including Magnificent Frigatebird, Masked Booby, Sooty Tern, and Brown Noddy. Roger Tory Peterson once wrote that the thousands of terns breeding in the Tortugas were “the number one ornithological spectacle on the continent.” Additionally, Fort Jefferson on Garden Key is the largest masonry structure in the country and is steeped in history. Its halls and chambers are at once haunting and beautiful, and many people visit the national park with the sole intent of exploring this architectural wonder.

Brown Booby

Brown Booby— Photo: Rafael Galvez

 

Our first dinner was filled with much enthusiasm during our first night. After introductions and a nice meal, we headed to the Key West Yacht Club, where the boat that would take us to the Dry Tortugas—the MV Playmate—was anchored and waiting for us. Aboard the boat, we were met by the crew and given an orientation. Very early the next morning, while most passengers were sleeping, our captain started the engines, and we set sail toward the Dry Tortugas archipelago. The weather was promising, although the region is renowned for the potential of sudden unexpected changes. As we left Key West behind, the first streaks of light lit the sky. The crew included a wonderful cook who spoiled us with an exciting array of great food. Soon after everyone had their first breakfast, we were all up at the top deck in front of the wheelhouse, scanning the relatively calm waters for pelagic birds. 

It did not take long for us to be rewarded with the first of our exciting seabirds—Audubon Shearwaters. At first we saw small groups of four or five, but soon we found dozens feeding on the surface and taking to flight as we approached. Our captain was great at reorienting the boat in pursuit of feeding flocks of birds. We soon found groups of Sooty Terns stirring up fish. The terns were very active and at times difficult to get close to. It did not take long for us to spot a couple of distant Bridled Terns amidst the fast-feeding Sooties.

Audubon's Shearwaters

Audubon’s Shearwaters— Photo: Rafael Galvez

 

As we continued towards the deeper waters of the Rebecca Channel, we started encountering Magnificent Frigatebirds, languidly flying at relatively low altitudes. We veered to make close inspections of various large markers and buoys along the way, and were rewarded with a number of new birds. At one of our first stops, we found our first Brown Booby, a subadult bird that took to flight as we approached. The following buoys would have a mixture of terns, including a group of beautiful Roseate Terns in pristine breeding plumage. During these stops and along the way we also encountered Forster’s and Common terns, Brown Noddies, and a couple of Pomarine Jaegers.

By late morning, we could finally see Fort Jefferson in the distance; as if built directly atop the water’s surface, no land was visible. The Dry Tortugas are composed of seven sandy islands that are very low above sea level, and are often changing with the tides and storms. Once we were within the boundaries of the archipelago, the deeper waters of the straits were replaced by the bright turquoise, light blue, and emerald-green hues distinctive of the Dry Tortugas.

We were treated to quite a show as we slowly sailed near Hospital Key, the site for the sole colony of Masked Boobies in the continental U.S. Dozens of boobies could be seen resting directly on the shallow sandy island. It did not take long for several birds to take flight and glide right over our boat. We could see them plunge into the water for fish directly in front of us, granting us fantastic views of this handsome seabird. As we approached Garden Key for our landing, hundreds of Sooty Terns and Brown Noddies could be seen taking off from their nesting grounds on Bush Key towards the emerald waters. Some of the birds flew so close that one could not get better looks.

Roseate Terns

Roseate Terns— Photo: Rafael Galvez

 

When we arrived at Garden Key, we went directly into Fort Jefferson’s parade grounds where several trees, shrubs, and open lawns give migratory birds an opportunity to feed and refuel before continuing their flights northward. Many Cattle Egrets were immediately evident, foraging on the lawn. Although the species is hardy and adaptable, the conditions in the Tortugas prove to be challenging. There are very limited feeding opportunities for birds on the islands, and many do not make it out alive. It was interesting to find a single Glossy Ibis amidst the egrets, a species that is not commonly seen in these islands.

The Buttonwoods and Seagrapes of Garden Key had a substantial number of migratory birds. At least two Black-and-white Warblers clung to branches; a close-by male Hooded Warbler foraged in the understory, allowing us very close looks—soon we would see more; Cape May and Blackpoll warblers darted back and forth between trees; and Common Yellowthroats could be seen here and there skulking in the deeper brush. It did not take us long to find the first Black-whiskered Vireo—a regional specialty that is often uncooperative. Most of these species we would see again and again all three days we birded the Tortugas. We also managed to add Ovenbird in the campground, American Redstarts at various locations, a couple of Northern Parulas and Yellow Warblers, fewer Black-throated Blue and Black-throated Greens, Prairies and even a Yellow-rumped Warbler. Palm Warblers were among the most common.

Hooded Warbler

Hooded Warbler— Photo: Rafael Galvez

 

Several Gray Kingbirds perched in snags within the parade ground. At least one Eastern Kingbird mingled with the Grays. Indigo Buntings could be heard often, and we managed to encounter a few here and there, moving through the key often. A nice surprise was finding a female Scarlet Tanager in the Seagrapes outside of the fort.

One of the biggest challenges when birding the Dry Tortugas is sorting through the thousands of Sooty Terns and Brown Noddies nesting in Bush Key with the hopes of finding an uncommon species. The swarm of thousands of birds flying back and forth and alighting on the thick vegetation is daunting. A few Bridled and Roseate terns have successfully nested on the island, and every now and then, Black Noddies show up. After sorting through countless Brown Noddies through the scope, we were fortunate to find a single Black Noddy perched amidst Browns; its size was noticeably smaller and its plumage more contrasting, once you put your sight on the bird.

Over the parade ground, many swallows could be seen foraging in a large mass. Most were Barn Swallows, although there were many Northern Rough-winged, a number of Cliff, and a couple of Bank. It was a great opportunity to hone in on our swallow identification skills, since many of the birds did not go far and were relatively easy to follow. Foraging over the parade ground were also some raptors. We often saw a Sharp-shinned Hawk that raced through the trees after songbirds. A couple of Merlins and a Northern Harrier were also seen cruising over the fort, and it did not take long for us to spot our first Peregrine Falcon.

Sooty Terns

Sooty Terns— Photo: Rafael Galvez

 

A favorite part of this tour tends to be our dinghy ride at sunset to cruise along Bush and Long Keys, and this year we were not disappointed. That final afternoon, as the sun lowered in the sky, we cruised the aquamarine waters while Sooties and Noddies swerved by the hundreds past our boat. We stopped at the frigatebird rookery to watch the gigantic Magnificents play in the gentle air. Some of the males could be seen displaying their inflated bright red throat pouches. Three Peregrine Falcons could be seen roosting on mangrove snags. White-rumped Sandpipers ran along the beach. It was a memorable way to finish a splendid day, surrounded by thousands of birds below the fiery sky. As the last streaks of light gleamed, the tropical air was peppered with “wide awake” calls of Sooty Terns.

Before sailing back to Key West, we had a final morning of birding in Garden Key. Some of the birds we had seen there the day before were still there, yet many had left. The clear skies and favorable winds the night before proved encouraging for migrants wishing to continue northward. Still, as had been the prior days, it was not difficult to find a Buttonwood filled with warblers, Black-and-whites clinging from branches, a Hooded male foraging in the understory, several Blackpolls and Cape Mays in the thick canopy, and a Black-whiskered Vireo working its way to top branches.

Fort Jefferson

Fort Jefferson— Photo: Rafael Galvez

 

During the boat ride back, we managed to add Sandwich and Least terns, making it ten species of terns for the trip! The winds had picked up by midmorning, and our ride back was slow and uneventful. As we approached Key West, more Roseate Terns could be seen careening by, and an Osprey wheeled lazily over the island city. We managed to see many migratory birds, many of which were already gaining on their northern destinations by the power of their own wings. We saw a number of regional breeding specialties, recently arrived from their wintering grounds in the Caribbean. A tour to the Dry Tortugas is always memorable, and this one was a great success.