Male frigate birds use their gular sac — a large throat bag — to attract female counterparts. During courtship, the male forces air into the sac making it look like a large red balloon. The males sit in groups with their balloon-like necks exposed waiting for a female to fly overhead. When one does, the males move their heads from side to side and shake their wings while making bird calls. If they succeed in attracting the female’s attention, she will land and sit beside her chosen mate.
Frigate birds are sometimes considered “pirate birds” as they harass other birds — especially Boobies — into dropping fish the other birds have caught. The frigate bird is so fast and precise they can sometimes catch the falling fish before it hits the water.