Situated on just off the most northern part of Isla Colón is Sway Cay, or otherwise known as Isla de los Pájaros. This small islet and its satellites are the only known nesting site in the southwest Caribbean for the Red-billed Tropicbird Phaethon aethereus. Although definite information is lacking, 20 to 30 pairs (and certainly less than 59) may breed at the site. It is also one of only three nesting sites of the Brown Booby Sula leucogaster on Panama's Caribbean coast. The site does not appear to be under any immediate threat, however, with the rise of ecotourism, Swan Cay deserves to be included within the system of protected areas in the Republic.

To the visitor Swan Cay appears as an offshore stack. A refuge for the Brown Booby, large nesting colonies are found as well as on Escudo de Veraguas island, located east of the Valiente Peninsula and some 17 km offshore.

When visiting Swan Cay one CAN NOT disembark on the island, as it is a marine preserve. You must observe the bird life from the tour boat. Tours to this island are normally full day tours, and include snorkeling at various spots. In addition, lunch is often enjoyed at the restaurants located at Playa Drago, which is just 15 minutes by boat from Sway Cay.

Here is a description of Swan Cay, by the renowned ornithologist Alexander Wetmore, in his Vol I of The Birds of the Republic of Panama, which stands true today:

Swan Cay, approximately 70 meters long, is a rounded quarter moon in shape, pierced by two openings through one end, and rises 55 meters at the highest point. On the southern side, sheltered from the northeastern trade winds, there is a small sandy beach below a higher level area. Bushes and other vegetation cover the summit, and there is a small clump of coconut palms at the low end.

As you approach Swan Cay by boat, the Red-billed Tropicbird Phaethon aethereus flies high overhead while others circle among the brown boobies that fly out as they notice people coming near. Tropicbirds soare easily, their long tail streamers undulating in the wind, graceful and attractive in every way.

On the leeward side of the islet several tropicbirds rest on nests placed on narrow ledges on the rock faces above the sea, sheltered by overhang above. Some of them are low down, one or two meters above the height of maximum storm waves, others higher. The eggs are oval, some broader than others, verging toward short-oval. The shell is pitted, and the ground color is dull white, but in most so solidly dotted with Natal brown to bone brown that the lighter base is almost completely obscured. In some the dots are more concentrated at the larger end, and occasional eggs have scattered irregular spots, or are less heavily marked so that the pale base color is seen.

Tropicbirds are beautiful seabirds found in warmer waters around the world. Adults have extremely long central tail feathers, which when fully developed may exceed the length of the body. The Red-billed Tropicbird has a red bill which appears to be heavy. It is almost all white with black primaries, a black stripe through the eye, and fine black barring on back and rump. Immatures lack the long tail feathers and have yellowish bill, coarser barring on back, and black eyestripe extends back to form partial nuchal collar. Its flight is energetic, dove-like. When swimming, the tail is cocked up out of the water. Their food is fish and squid, obtained by diving from considerable heights.

Boobies range worldwide through tropical seas. In their search for food they are birds of the sea, the isthmus of Panama forms a barrier of land that they do not cross. The adult has neck and upper breast brownish black, contrasting sharply with the white of the lower breast and abdomen. Immature is dark grayish brown, with the under surface paler, almost mottled, usually with a faint indication of the sharply defined line that in the adult separates the white and dark areas of the breast. Bill and legs are greenish to yellow.

Brown boobies live mainly around small offshore islands. They are more abundant in the Gulf of Panama than in the Caribbean. They often attempt to fly off with bait being trolled behind fishing boats.