Fregatidae

Fregatidae are large seabirds usually found over tropical oceans. They are large, black-and-white or completely black, with long wings and deeply forked tails. The males have colored inflatable throat pouches. They do not swim or walk and cannot take off from a flat surface. Having the largest wingspan-to-body-weight ratio of any bird, they are essentially aerial, able to stay aloft for more than a week.