40 Fun Facts About Frigatebirds

What did brain recordings reveal about how frigatebirds cope on ocean flights lasting many days?

They sleep while flying, but for only about 40 minutes a day, a fraction of what they get ashore, and sometimes with just one half of the brain at a time.

What colour is the balloon-like throat sac a male frigatebird inflates to attract passing females?

Red is the colour, and the sac takes about 20 minutes to pump up. It deflates so slowly that a startled male may fly off with it still swollen.

A great frigatebird tracked by satellite over the Indian Ocean stayed airborne for roughly how long?

Two months aloft was the tally for a bird that rode rising air and barely flapped. Frigatebirds have also been tracked above 4,000 metres, in freezing air.

Why do frigatebirds never settle on the sea, unlike almost every other ocean-going bird?

They are not waterproof: frigatebirds make very little preen oil, so their plumage would soon be sodden. They even bathe on the wing, dipping low to splash the surface.

A frigatebird's air-filled skeleton is only about 5% of its weight, far less than which other part?

Its feathers weigh more than its bones: plumage and flight muscles each make up about a quarter of the bird. That light frame lets it hang on rising air for days.

Which nickname did English sailors in the Caribbean give the frigatebird in the 1600s?

Man-of-war bird matched the French name behind 'frigatebird': la frégate was a fast warship. Both names nod to the way the bird chases down other seabirds and robs them.

In Hawaii the great frigatebird is known as the ʻiwa, a name with which unflattering meaning?

Thief is the meaning, a nod to the bird's habit of harassing other seabirds until they give up a meal. Even so, the ʻiwa catches most of its food for itself.

Which seabirds are the frigatebird's favourite victims, chased in mid-air until they throw up?

Boobies are the favourite target, yet the raids pay poorly: one study found stolen meals supplied only about 5% of the food a frigatebird needs.

Why did sailors in the age of exploration treat the sight of a frigatebird as a good omen?

Land was near, sailors reasoned, since a frigatebird cannot rest on the water. In fact the birds may forage up to 500 km from shore.

The largest frigatebird species, found from Florida to Brazil, has which grand word in its name?

Magnificent frigatebirds measure up to 114 cm long, with a wingspan that can top 2.4 metres. Their Latin species name, magnificens, means splendidly.

Which prey tops a great frigatebird's diet, often driven to the surface by bigger hunters below?

Flying fish top the menu, caught at the surface or plucked from the air as they glide away from predators. Squid are also taken.

Fishing crews head for circling frigatebirds because the birds often mark schools of which fish?

Tuna push small prey up to the surface, where frigatebirds swoop in on the chase. The link cuts both ways: overfishing of big predators leaves the birds with less to eat.

Which Pacific nation's flag shows a golden frigatebird above a rising sun and ocean waves?

Kiribati took the design from the colonial arms of the Gilbert and Ellice Islands. On the flag the bird stands for command of the sea, freedom and the nation's dance patterns.

Where in the Pacific do carvings of the birdman Tangata manu show a frigatebird's hooked beak?

Easter Island's Rapa Nui people venerated the great frigatebird, and the birdman won his title in a ritual contest. The bird itself no longer nests on the island.

Besides swimming, which everyday skill of most seabirds is all but beyond a frigatebird?

Walking defeats them because their legs are so short and their feet so weak. They also struggle to take off from the sea, so they keep clear of it.

Along coasts, frigatebirds will also swoop on the newly hatched young of which reptiles?

Sea turtles are easy pickings as hatchlings cross the beach, and frigatebirds lift them without ever touching down. The birds also scavenge scraps around fishing boats.

On Caribbean cays, frigatebirds usually build their flimsy nest platforms in which coastal trees?

Mangroves hold most of the nests, built mostly by the female from twigs the male brings. Where no trees or bushes grow, frigatebirds will nest on bare ground.

Frigatebirds soar on thermals, unlike which seabirds that ride the winds made by ocean waves?

Albatrosses are dynamic soarers, drawing their lift from wind over the waves. Frigatebirds instead circle upward on columns of warm air, rarely needing to flap.

Which term describes the frigatebird's habit of forcing other seabirds to give up their food?

Kleptoparasitism is rarer than its fame suggests: stolen meals are only a supplement to what frigatebirds catch for themselves.

Which explorer's journal of his first Atlantic crossing describes a frigatebird forcing other seabirds to vomit?

Columbus's journal for 29 September 1492, written in mid-ocean, says the bird made other seabirds throw up their meals and that many lived in the Cape Verde Islands. That colony is now probably gone.

A soaring frigatebird's long pointed wings and tail give it a silhouette likened to which letter?

W is the shape, and with their dark plumage and sheer size it makes frigatebirds hard to mistake: no other seabird looks really similar.

The Spanish name for the frigatebird, rabihorcado, describes which feature of the bird?

Forked tail is the meaning, and frigatebirds use that tail as a rudder when twisting after other birds in flight.

Frigatebirds gain height without flapping by riding warm updrafts beneath which type of cloud?

Cumulus clouds sit on top of rising warm air, a free lift for a bird that can soar for days and only rarely flaps its wings.

Frigatebirds live where which steady air currents supply the breeze their flight needs?

Trade winds blow steadily across the tropics, which is why frigatebirds turn up only as rare strays in cooler regions and never near the poles.

Which substance soon coats and cements the loosely woven twig nest of a frigatebird pair?

Guano, the birds' own droppings, hardens the flimsy platform. Little else is done to maintain it, and some nests fall apart before the season ends.

Fledgling great frigatebirds hone their flying skills in a chase game played with which object?

A stick is the toy: one youngster carries it, others give chase, and when it is dropped a chaser tries to catch it before it hits the water.

Frigatebird parents feed their fledged young for even longer in years hit by which climate event?

El Niño years stretch a period of care that already runs for up to 428 days after a chick first flies. No other bird looks after its fledged young for so long.

Unlike most seabirds, frigatebirds will swoop low over a pond or stream for which purpose?

To drink fresh water, they skim low and gulp with the bill, never touching down. It is a habit few other ocean birds share.

Islanders in Tuvalu and nearby Pacific atolls reportedly used tame frigatebirds for which task?

Carrying messages worked because a tame frigatebird taken to another island could be trusted to fly straight back to its home.

One rare frigatebird breeds only on which Australian territory, long mined for phosphate?

Christmas Island holds every nest of its namesake frigatebird, in just four main colonies. Wartime clearing of breeding habitat and dust from the mines have both cut its numbers.

Which Caribbean nation has the frigatebird as national bird and a vast colony at Codrington Lagoon?

Antigua and Barbuda guards the colony as a bird sanctuary, one of Barbuda's main tourist draws. Hurricane Irma killed that season's chicks in 2017, but the adults were nesting again within weeks.

Feral cats wiped out the frigatebird colonies of which British outpost in the South Atlantic?

Ascension Island lost its colonies after cats arrived in 1815, and the birds clung on atop a rock stack just offshore. Once the cats were removed, two pairs came back to nest in 2012.

DNA tests found a long-isolated population of the largest frigatebird in which archipelago?

Galápagos birds have not swapped genes with the rest of their species for several hundred thousand years, even though mainland frigatebirds mix freely across the Isthmus of Panama.

Which tiny Pacific nation has a tradition of catching frigatebirds with a thrown, weighted line?

Nauru's catchers sling the line at birds lured in by tame decoys, tangling a wing to bring one down. The frigatebird is the national bird and sits on the coat of arms.

Which plunge-divers sit with cormorants and darters in the group closest to frigatebirds?

Gannets and their relatives form the sister group to frigatebirds, a link confirmed by genetic studies. Earlier DNA work had placed frigatebirds alongside penguins and loons.

Carl Linnaeus first classified frigatebirds in the same genus as which large-billed waterbirds?

Pelicans shared the genus Pelecanus with frigatebirds in Linnaeus's scheme, but DNA has since shown the two are not close. Frigatebirds now have a family all to themselves.

Frigatebirds sometimes seize which seabirds by their long tail plumes to make them give up a meal?

Tropicbirds trail streamers that make a handy grip for a pursuer. Frigatebirds often circle high above a colony, waiting for parents to fly home loaded with food.

Frigatebirds hold which record among all living birds, the secret of their effortless soaring?

Most wing area per weight means the lowest wing loading of any bird, so even the faint lift over warm tropical seas is enough to carry a frigatebird upward.

The oldest frigatebird fossils, about 50 million years old, date from which geological epoch?

Eocene fossils from Wyoming belong to Limnofregata, a relative with longer legs and a shorter, less hooked bill that lived on inland waters rather than at sea.

Frigatebirds rob gulls and petrels of their catch, and have even been seen robbing which bird of prey?

Ospreys carry what they catch in their talons, which makes them a tempting target for a faster, more agile pirate. Frigatebirds simply chase a victim until it lets go of its meal.