MASKED BOOBY

The masked booby (Sula dactylatra) is the biggest of the booby species with a wingspan up to five feet across. It is colored black and white, rather plain compared to its more colorful relatives. Also, its courtship is less elaborate, but it is a beautiful bird. It is a ground nester, like the blue-footed booby so there is some competition for nest space. However, the masked booby tends to prefer rocky cliff areas, which tend to be on the periphery of the blue-foot colonies. This not only reduces competition but also means the masked boobies have the benefit of strong winds to help them get aloft.

Its name comes from the "mask" of dark facial skin at the base of the bill. The masked booby's feet are a dull gray, and they are not used in courtship display.

Masked boobies are abundant throughout the Galapagos, and have large colonies on Hood Island and Tower Island. Like other members of the Sulidae (Gannet) family, they are plunge-divers. To avoid competition with the other species, they feed in deeper waters between the islands, rather than close to shore like the blue-footed booby or the open ocean like the red-footed booby. The Galapagos population of masked boobies is considered to be an endemic subspecies (Sula dactylatra granti).

The pictures on this page were taken on Tower Island.
To learn more, see masked booby natural history information and Boobies—general information

Masked booby courtship seems a rather low-key affair compared to the drama of the blue-footed booby's. Pairs preen each other around the head and neck and often present each other with small gifts of twigs or feathers, as above. These precious gifts are then carefully placed in the nest area—a vague circle of scraped earth lined with guano, pebbles and other material. (You can see this in the bottom right corner of the photo.) This is a vestigial nesting behavior, evolved from more complex nest-building activity. Masked boobies lay two eggs, but invariably raise only one chick. If two eggs hatch, the older chick will kill the other—a behavior called siblicide. (what does this mean?) Siblicide might seem brutal to us, but for the booby parents, it ensures the success of their breeding effort should one of the chicks die from accident, disease or predation.

After about three months in the nest, the masked booby chick moves away periodically. Before this the chick must stay in the nest ring (mentioned above) or it will be abandoned. It still receives food from the parents as it will for until they learn the difficult skills of plunge-diving. By the time it is seven months old (about the age of the curious individual above) the young booby will begin to flex its wings with tremendous flapping around, occasionally lifting a few feet from the ground. Once the flight muscles are developed enough, it will take to the air and begin its life as an adult. Full adult plumage grows after the second year.