Magnificent Frigatebird

Birds are the most accomplished aeronauts the world has ever seen. They fly high and low, at great speed, and very slowly. And always with extraordinary precision and control.
~ David Attenborough

The magnificent frigatebird, Fregata magnificens, is the largest of five species of frigatebirds, and the only one typically found in North America. Both the genus and common names are derived from the French mariners' name for the bird, la frégate, meaning a frigate or fast warship. Larger than a brown pelican but smaller than an American white pelican, magnificent frigatebirds are mostly black with long, angular wings. The body is about three feet in length, the wingspan is over seven feet, and they weigh up to four pounds. They have a deeply forked tail, often held closed in a point. Their gray bill is long and sturdy with a prominently hooked tip. Females have a white chest and are larger than males. Juveniles start with a white head and belly that gradually darken. In the breeding season, males have a bright red throat pouch (called the gular pouch) that they puff out to attract a mate. Frigatebirds are the only seabirds in which the male and female look strikingly different.

In the non-breeding season, magnificent frigatebirds can be found from the coast of North Carolina south to Florida, west to Texas, and on the coast of California. During breeding season, they’re mostly found along coastal Florida and on mangrove islands in the tropical Atlantic and Pacific Oceans. Though they sometimes travel inland, such as crossing the Isthmus of Panama from one ocean to the other, they are rarely seen far inland around fresh water. Despite having dark plumage in tropical climates, frigatebirds don’t overheat. They ruffle feathers to lift them away from the skin and improve air circulation, and can extend and upturn their wings to expose the hot undersurface to the air. They also place their heads in the shade of their wings, and males frequently flutter their gular pouches.

Unlike all other marine birds, frigatebirds do not have waterproof plumage, so they can’t land on the surface of the ocean. They produce very little oil from their uropygial (preening) glands so their feathers become sodden if they get too wet. Luckily, they’re able to stay aloft for insanely long distances and periods of time by taking advantage of air currents – soaring high on warm air rising during the day and gliding along the prevailing winds, relying on them to travel far from the shore with minimal effort. Sometimes, they can shoot up into the air at rates of 13 feet to 16 feet per second just by catching a ride on a current going the right way. They rarely flap their wings, but when they do their wingbeats are slow and deep. In a 2016 study, researchers found that some great frigatebirds were spending as many as two months in the air without ever touching the ground. Their gracefulness ends as soon as they land. Their strong toes help them hold onto branches, posts, and boat masts, but their small feet and short legs make for quite a sight when they walk. Fortunately, they are almost continuously on the wing, with a morphology and flight pattern that result in very energy-efficient foraging.

Magnificent frigatebirds typically eat flying fish, tuna, herring, and squid, which they snatch from the surface of the water (often the prey have been chased upwards by underwater predators, such as tuna). However, they’re opportunistic and will also take plankton, crustaceans, jellyfish, hatchling turtles, young birds, and discarded fish from fishing boats. At times, they prey directly on eggs and nestlings of other seabirds, including boobies, petrels, shearwaters, and terns. Though they are frequently seen soaring, frigatebirds are masters of pursuit – sometimes referred to as the "man-o-war bird" because of their kleptoparasitic feeding behavior.  Frigatebirds will harass other birds, forcing them to regurgitate recently captured food, which the frigatebird then steals before it hits the water. Learning how to chase other birds and steal meals takes practice. Young frigatebirds hold sticks in their mouths and chase each other. When one of them drops the stick, the other dives below to retrieve it. On average, kleptoparasitism only represents about five percent of a frigatebird’s diet. It’s mostly a supplement to their regular hunting.

Frigatebirds typically breed on remote islands with mangroves or other low trees and shrubs, in colonies of up to 5000 birds. Within these colonies, they usually nest in groups of five to fifteen pairs. Nests are packed into small areas and are often within striking distance of another nest. Breeding can occur at any time of year, as long as the weather is dry and food is plentiful. Males have elaborate mating displays. Up to thirty individuals will group together, displaying to females flying overhead by pointing their bills upwards, inflating their red gular pouches and vibrating their outstretched wings, showing the lighter wing undersurfaces in the process. They also vibrate their bills, producing a drumming sound, and sometimes give a whistling call. The female descends to join the male she has chosen and allows him to take her bill in his. After copulation, it’s generally the male who gathers sticks and the female who constructs the nest (on the male's display perch). The male gathers sticks from trees and shrubs, but also steals them from other males. The female arranges them into a flimsy platform about nine to fourteen inches wide and cements them with guano (seabird excrement). Nest building takes several days. Each female lays a single white egg, and parents take turns incubating the egg for about 50 days. Chicks are naked and helpless upon hatching, soon developing a white down. They are fed by both parents and continuously guarded for the first several weeks, since other members of the colony will eat unattended eggs or young. Males depart after about three months, leaving the female to continue rearing the chick for another six to nine months. Chicks fledge anywhere from four to six months old. It takes so long to raise a frigatebird chick that females only breed every other year. The duration of parental care is among the longest of any bird species. Frigatebirds only breed once they have acquired full adult plumage – eight to nine years for females and ten to eleven years for males. In 2002, thirty-five great frigatebirds were recovered from the Hawaiian Islands. Of these, ten were older than 37 years, and one was at least 44 years of age. The oldest known magnificent frigatebird was at least 19 years, 9 months old when it was recaptured and rereleased in the Lesser Antilles.

Despite their slow maturity and low reproductive rate, magnificent frigatebirds are classified as Least Concern on the IUCN Red List and have a generally increasing population trend. This hopefully means we will enjoy these magnificent birds for many years to come.

Birds are the most popular group in the animal kingdom. We feed them and tame them and think we know them. And yet they inhabit a world which is really rather mysterious.
~ David Attenborough

Where I learned about frigatebirds, and you can too!

*Special thanks to Rockport kayak fishing guide Fred Krebs for the inspiration and knowledge he shared on our kayak trip.

All About Birds: The Cornell Lab of Ornithology
www.allaboutbirds.org/guide/Magnificent_Frigatebird/overview

Audubon Guide to North American Birds
www.audubon.org/field-guide/bird/magnificent-frigatebird

eBird
ebird.org/species/magfri

Nature Works
nhpbs.org/natureworks/magnificentfrigate.htm

IUCN Red List
www.iucnredlist.org/species/22697724/132597208

Popular Science
www.popsci.com/how-frigate-birds-stay-in-air-for-months-at-time

Science
science.sciencemag.org/content/353/6294/26

Encyclopaedia Britannica
www.britannica.com/animal/frigate-bird

Handbook of the Birds of the World
www.hbw.com/family/frigatebirds-fregatidae

New Zealand Birds Online
nzbirdsonline.org.nz/sites/all/files/142_Great%20Frigatebird.pdf#2

Wikipedia
en.wikipedia.org/wiki/Frigatebird