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.
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 areaa 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 othera 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.