Tuesday, August 26, 2014

PELAGIC BIRDS ARE OUT THERE


Most people have heard of albatrosses; few people have seen them. But every summer they are common offshore visitors to the Pacific Northwest. Boat trips out of Westport, Washington, and Newport, Oregon, go out 20-30 miles and can dependably find albatrosses and a host of other pelagic birds. Pelagic means “out of sight of land,” and there are a lot of pelagic birds. Because birds can fly, they roam all over the ocean’s surface in search of food.

Of course, all birds lay their eggs in nests on land or floating in freshwater wetlands, so you wouldn’t think they would wander far out in the ocean, but in fact they do. Many species fly thousands of miles when they are away from their breeding grounds for half the year or more. Black-footed Albatrosses breed in the Leeward Hawaiian Islands, but they roam to our coast, 3000 miles away, when not at home. Even more astonishing, when feeding young a Laysan Albatross may fly from the same islands up to Alaska’s Aleutian Islands, 1500 miles away, on a single multi-day foraging trip!

Sooty Shearwaters fly several tens of thousands of miles on their migrations from their breeding grounds in New Zealand to their wintering grounds in the North Pacific, taking an extended figure-8 path that has them flying counter-clockwise around the North Pacific. Meanwhile, Pink-footed Shearwaters make almost as long a flight from islands off the coast of Chile.

The Northern Fulmars that visit us, on the other hand, breed in islands in and around the Bering Sea, so they have to fly south to approach our coast. The Fork-tailed Storm-Petrels we see offshore come from much closer at hand, the string of islands that stretch along the outer coast from off Cape Flattery to off Point Grenville.

All of these birds are in the order Procellariiformes, called “tube-noses,” because of their tubular nostrils. Members of this group all take their food from on or near the ocean’s surface. Some of them skim the surface, others dive down to several meters or more. They all feed on fishes, squids, and planktonic crustaceans—the larger the bird, the larger the prey. And they all have an excellent sense of smell, which helps them find smelly prey at sea and their nest site back on their home island.

These birds are supremely adapted for flying very long distances. Their long, narrow wings are perfect gliding surfaces. With any air movement at all, the larger species surf the wind, rising into it with the lift it provides, then falling off to the side to gain speed to turn and rise up again. Watch them on a windy day to see their roller-coaster flight over the ocean. And if you’re seasick-prone, you don’t have to go out on a boat. At times in summer you can see Sooty Shearwaters from shore in astronomical numbers.


Dennis Paulson
Nature Blog Network