The Magnificent Frigatebird

2010 Howard Platt May 2010 Nature

 By Howard Platt from the May 2010 Edition

The opportunity and willingness to take what one needs from others on the high seas, and the speed and agility to get away with it these were, and are still, the marks of a pirate.

The old pirates along the coast of the Americas relied on the speed and maneuverability of their ships to succeed in their greedy ways. The magnificent frigate bird has a body perfectly designed for this task. A huge wing span over six feet when full grown and low body weight combine to give these birds unparalleled buoyancy in the air. Their form and tail add outstanding aerodynamic maneuverability.

You can see them high in the sky, soaring effortlessly for hours at a time. Unlike most other sea birds the male and female look different. Males are all black except for a bright red throat pouch which becomes enlarged at breeding time. Females are black, but have a white breast and lower neck sides, a brown band on the wings and a blue eye ring. Immature birds have a white head and under parts.

Frigatebirds never land in the water and are usually only seen in flight. They can swoop down to the surface to pick off jellyfish, fish, or other life on the surface of the ocean. Their skill at snatching food from the ocean with their long beak without even getting feathers wet can be witnessed when children leave a few small fish on the beach. Frigatebirds will dive down, one after another, and take the fish without losing speed or leaving marks in the sand!

Their aerobatic abilities are also easy seen when children throw small fish into the air from the beach. The aerial ballet which ensues is often hard to follow, until the victor leaves with the prize. It is hard to understand how the air is not full of collisions.

But their reputation as the Man O’War comes from chasing and harassing other sea birds such as Terns, Gulls and Boobies, and forcing them to give up their catch. They even nest close to Boobies and Gannets to make the thieving easier. Perennial pirates, they are doing as well today as they did in times of old.

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