Have you ever seen a Booby Bird?

Debra Hess
Yankee Freedom II Naturalist

A trip aboard the Yankee Freedom II to the Dry Tortugas National Park will allow you to observe as many as three species of Booby Birds. The Masked Booby—largest of the Booby species w/ a wingspan of 62 inches, a weight of 3.3 pounds and a length of 32 inches—nest on Hospital Key near Fort Jefferson in the Dry Tortugas. This is the only nesting Booby species at any National Park in the continental U.S. A few Masked Booby birds nested on Middle Key in the 1980s and their nests were frequently washed out by late spring storms. In recent years as many as 25 pairs of Masked Booby birds have nested on Hospital Key and are successfully raising chicks. The Masked Booby birds are observed almost every day on our trips to Ft. Jefferson and the Dry Tortugas National Park, usually in the area of Hospital Key. In addition to the Masked Booby, the Brown Booby may be sighted both at sea and on navigational markers near Fort Jefferson. Juvenile Red Footed Boobys have been observed roosting with the magnificent Frigatebirds during the late winter and spring. Neither of these species has been recorded breeding in the Tortugas.

Booby birds belong to the family Sulidae which includes all of the tropical Booby species and also the larger Gannet which nests in cliffs along the colder waters of the north Atlantic. Booby birds are diving seabirds with keen binocular vision. Fish or squid are sighted from above the sea and a plunge dive (almost torpedo-like) occurs. The birds will begin the dive from 30-60 feet or more, enter into an almost vertical descent, tuck in their wings tightly just above the water and pierce the water cleanly. The Masked Booby seems to favor Flying Fish in it’s diet which we see in great abundance in Rebecca Channel, a deep water passage we traverse before Dry Tortugas National Park. The name Booby is derived from the Spanish “bobo” or clown, as these birds were easily approached and killed by Spanish explorers for food both meat and eggs. This name also applies well to the Booby’s breeding behavior. These birds are known to raise and lower their heads and tails as well as waving their large webbed feet in courtship. Many of the Booby species have brightly colored feet. This clown-like behavior, aerial displays and gift giving are all important parts of the Booby’s courtship.

In the Dry Tortugas, the Masked Booby nests in the sand. Some nests are adorned with shells and seaweed, perhaps gifts of courtship. Two eggs are laid. The Booby species practices siblicide, meaning the first hatched chick will push the second chick away where it will fall victim to a predator or starvation. Of course, if the first chick does not hatch, the second egg may provide a chick to raise. The chicks are fed regurgitated fish 1-2 times per day. Both parents incubate and feed the young. Unlike most birds with brood patches (areas on the chest with less feathers to warm the chicks,) Boobies lack those and instead use their large feet to warm and protect their chicks. Chicks are born in the spring and early summer and fledge in 109-151 days. Breeding starts at about four years, and the birds may live as long as twenty years. They are monogamous which means the birds mate with the same bird every season. If a mate disappears or is killed, they may choose another mate. Although common through out tropical waters, Booby birds are not a common sight at National Parks in the United States.

Join the Yankee Freedom II to visit the Masked Booby on Hospital Key In the Dry Tortugas Fort Jefferson National Park.

Masked Booby Bird Cleared for Landing Masked Booby on Nest Masked Booby in Flight

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