52. Suliformes (Gannets, Boobies)

The bird family Sulidae comprises the gannets and boobies. Collectively called sulids, they are medium-large coastal seabirds that plunge-dive for fish and similar prey. All species feed entirely at sea, mostly on mid-sized fish and similarly-sized marine invertebrates. Many species feed communally, and some species follow fishing boats to scavenge discarded bycatch and chum. The typical hunting behavior is a dive from mid-air, taking the bird a meter or two under water. If prey manages to escape the diving birds at first, they may give chase using their legs and wings for underwater swimming. All sulids breed in colonies. Males examine the colony area in flight and then pick a nest site, which they defend by fighting and by territorial displays. Males then advertise to females by a special display and call. The display behavior is characteristic, though not as diverse as the numerous variations found among the cormorants; it typically includes the male shaking its head.