Frigatebirds are remarkable for being capable of staying in flight for extended periods covering several days and nights, and may sleep while on the wing. Like other frigatebirds, this species uses thermals to soar to heights of up to 2,500 metres, gliding downwards and climbing again in succession, with little need for wing flapping. This effortless flight allows long distances to be covered with minimal energetic cost, enabling the magnificent frigatebird to survive over tropical waters where food is scarce (4). The lack of waterproof plumage means that this species obtains most of its prey either just above, floating on, or submerged a few centimetres below the water surface. As such, its main source of prey is airborne flying fish, but it also takes squid, jellyfish and scraps discarded by boats, and will often feed over tuna and other predatory fish that drive smaller fish species to the surface. In addition to catching prey, the magnificent frigatebird will sometimes harass other bird species on the wing, forcing them to release food that they have recently caught, which is then snatched from mid-air by this species before it reaches the water. When not airborne, the magnificent frigatebird perches in trees, bushes or, less preferably, on the ground. A gregarious species, roosting takes place in large groups, where, during the day, individuals display a remarkable sunning posture, involving sitting upright with the wings fully extended to the sides, exposing the chest and underwings to the sun. (2).
The breeding behaviour of the magnificent frigatebird is highly unusual and dramatic. During courtship (which generally occurs between August and October), the males gather in groups of various sizes, with gular sacs inflated, bills clattering, and wings and heads waving, while making calls to attract females flying overhead. Once a pair decides to mate, they commence construction of a nest, usually in a tree or bush, with the male providing material such as twigs, while the female does the actual building. After mating, a single egg is laid, which is incubated for between 53 and 61 days by both parent birds. The chick, which takes around 22 weeks to fledge, is brooded and fed by both sexes for the first seven to twelve weeks, after which time the male leaves, and the female assumes full responsibility for raising the chick, providing food until fully fledged, and then for a further four to nine months (2). This extended period of parental care exhibited by all frigatebirds is the longest of all birds (4), and means that the female can only breed in alternate years (2). In contrast, by abandoning parental duties relatively early on, the male is able to breed with a new partner each year. Frigatebirds are the only seabirds known in which the sexes breed on cycles of different lengths (2).