BirdNote; Albatross Surfs the Wind

This is BirdNote.

[Sound of wind and waves]

Out in the North Pacific, an albatross flies in the wake of a ship. This large bird has a wingspan of about seven feet, and it’s completely at home in the harsh winds of the open ocean. It soars back and forth, above the ship’s wake, sometimes rising a hundred feet in the air, then coasting back down near the surface. With its wings slightly arched, an albatross can go for more than a day without flapping even once.

So how does this work? How can it keep up with the ship without flapping its wings?

The albatross knows how to use differences in wind speed to coast through the sky, a feat called “dynamic soaring.” Due to friction with the waves, the speed of the wind close to the water’s surface is much slower than it is higher up. By moving from the faster high air to the slower low air or vice versa, the albatross is propelled forward. And so, in a series of sinuous loops, the albatross surfs the wind, up and down, repeating the pattern over and over again as it moves thousands of miles across the ocean.

For BirdNote, I’m Michael Stein.