We saw many Great Frigate birds. They are magnificent black birds with forked tails that obtain food by diving and grabbing fish or other things. They are also kleptoparasites and can be seen harassing other flying birds such that they drop their prey and then the frigate swoops down and catches the prey itself. They are huge with a wingspan up to 90 inches. The male frigate bird has this red pouch that he can puff up and rests on a branch or the ground attempting to catch a mate. They have some lovely purpleish/green iridescent feathers, too. At one point on the boat there was a frigate just hovering effortlessly 30 feet above the top deck keeping up with the travel. It just adjusted its wings slightly to keep on course and did this for at least ten minutes. They supposedly have the largest wing area/body mass ratio of any bird.