The Magnificent Frigate Bird

About Guy 

I was trolling for blue marlin off NW point when I saw the bird circling from over a mile away and headed over toward it, picking up my trolling speed a bit. The bird dipped suddenly, powerful wing beats pushing it close to the choppy surface. Flying fish burst out of the wave in front of the bird, and skittered away.

Its speed and anticipation were perfect as the frigate bird intercepted a large black-winged flying fish, and grabbed it in its pointed jaws, struggling to gain height and get away from the water. I watched as the frigate bird climbed with its heavy load, then dropped it purposely to retake the fish by the head and try to swallow it.

It caught the flying fish in mid air, and then swallowed it head first, shuffled its feathers in satisfaction, and began circling again. Then it easily dodged a late comer, another frigate bird trying to steal its catch.

What a way to earn a living! The big black-winged flying fish, which are common around the Cayman Islands, are more than a mouthful for the frigates, and other occasions I have seen the frigates drop the fish, which is then snapped up by a lurking dolphin fish.

These feathered buccaneers of the tropic seas are the most aerodynamic of the water birds. Their slender bodies, long pointed wings and characteristic scissor tail make for a very graceful animal.

Despite their fully webbed feet, the swimming abilities of their close relatives and the fact that they spend all of their lives over the water getting most of their food from the sea, frigate birds do not enter the water of their own accord. If they do land in it accidentally, their feathers soon become waterlogged, and they have difficulty taking flight again.

However on a recent visit to one of the Galapagos Islands, I witnessed frigate birds flying off the ocean far below to the top of a volcanic crater which had a small lake filled with rain water. The frigates would immerse their bodies in the water while still flying along, but would not get their wings wet, or sit on the water. They would also drink the fresh water.

The frigate bird, dolphin bird, tijereta or “man-o-war” bird as they are sometimes called, are equally inept on land, and need a high place to roost, and are often seen on channel markers in North Sound. They spend most of their time soaring over the open ocean, usually within sight of land, though I have seen them 150 miles offshore.

Their flight is little short of miraculous. Their light body, weighing only a couple of pounds, and six to seven feet wingspan has the greatest wing surface area to body ration of any bird. Frigate birds can out-manoeuvre all other sea birds and do so to harass them into giving up their hard earned food.

Frigate birds are known for their ability to pirate food from pelicans, boobies, terns and other frigate birds. Known as clepto-parasitism, they will chase down other sea birds returning to their roost from the feeding grounds, and peck them forcing the victim to drop its food which the frigates them catch before it hits the water, or deftly picks it from the surface. Fish form the mainstay of their diet, and they search the surface for oceanic predatory species that drive baitfish to the surface and so within range of the frigate bird’s accurate beak.

The range of their diet is varied and they can pick up anything floating at the surface, squid, young turtles, and dead fish. Frigates frequent the George Town waterfront where local fishermen are cleaning their catch.

On the other hand, I have seen frigates pick up floating Sargassum weed to reveal and expose small fish hiding from predatory tunas hunting beneath them. There seems to be no benefit to the bird for performing this unusual service.

While some frigate birds nest on Grand Cayman, the majority nest on Little Cayman, along with a large colony of red footed boobies. The frigate bird habitually preys on the young of colonial nesting sea birds, so every colony has its attendant frigate birds hanging in the breeze overhead, waiting for a chick to be exposed or unattended even for a few seconds. The marauder swiftly swoops in and snatches the chick from its nest.

They build a frail nest of sticks in low bushes or mangroves, but sometimes on the ground. The male picks the spot, stakes it out with a few twigs, and sits there inflating his throat pouch and beating his wings to attract his future mate.

The male’s gular pouch is normally orange in colour but it turns bright red in courting season, and it is inflated like a small balloon. It will stay inflated for hours, until he is selected by a female and she adds twigs to the nest and protects it from his neighbours. Both parents share the brooding during the six-week incubation period, feeding and guarding the young.

The chicks hatch blind and naked, but are soon covered with white down. In their immature plumage all are white headed, and it takes them two to three years to assume the full black adult dress, the males with a red throat patch, the females with white chest patch.

Frigates are frequently the subject of my paintings, as they interact with the oceanic predators I love to paint, the billfish, tunas, and dolphin fish. On a memorable filming trip near Isla Mujeres, Mexico, I was diving and filming the schools of sailfish that were feeding on Spanish sardines which they corralled into tight bait schools.

We located the feeding frenzies because the frigate birds formed a vortex, a mass of swirling birds, waiting for their chance to pluck a sardine driving to the surface, trying to escape the slashing bill of the sailfish beneath. It was quite a sight to have fifty sailfish circling around, the baitfish in a tight ball, and clearly visible above are the ever attendant, patient frigate birds.

The frigate bird is my eye in the sky when I am fishing, and to see one and watch one soaring on the ocean breeze, or see one swooping on a flying fish is to witness one of nature’s finest creations at work.

It is our collective responsibility to maintain the biodiversity of marine ecosystems, and ensure the survival of all species on the planet.
Good fishing, safe diving.
Guy Harvey PhD.