The Blue-footed Booby's diet consists entirely of fish. Blue-footed Boobies are specialized fish eaters feeding on school fish like sardines, anchovies, mackerel, and flying fish. They also feed on squid and offal. It dives into the ocean, sometimes from a great height, and swims underwater in pursuit of its prey. It hunts singly, in pairs or in larger flocks. They travel in parties of 12 or so to areas of water with large schools of small fish. When the lead bird sees a fish shoal in the water, it will signal the rest of the group and they will all dive together to catch the fish. Surprisingly, individuals do not eat with the hunting group, preferring to eat on their own, usually in the early morning or late afternoon. When they spot a school they will all dive in unison. They will point their bodies down like a torpedo and dive into the water. Plunge diving can be done from heights of 33-100ft and even up to 330 ft (100 m). These birds hit the water around 60 mph (97 km/h) and can go to depths of 82 ft (25 m) below the water surface. The prey is usually eaten while the bird is still under water. Males and females fish differently which could contribute to the reasons that blue foots, unlike other boobies raise more than one young. The male is smaller and the tail is larger for its body which enables the male to fish in shallow areas instead of just deep waters. The tail can flatten out easier enabling him to change direction in the shallow water. The female is larger and can carry more food. The food is then regurgitated to the young. The males feed the young for the first part of the incubation period. This is done because the males can bring back food quicker than the female. When the demand for more food takes over the female provides the food to the young.
Info taken from http://en.wikipedia.org/wiki/Blue-footed_Booby