Shearwater Migration


(This 814th Buffalo Sunday News column was first published on November 5, 2006.)


A few years ago I joined a group of birders on a pelagic trip. (Pelagic relates to the open ocean.) We drove to the south shore of Long Island where we boarded a small ship. On it we headed out into the Atlantic -- over the Hudson Canyon -- to look for sea birds.


It was an interesting trip and I enjoyed it very much, but it was not very comfortable. There was a great deal of pitching and rolling. Even as a former naval officer, I worried about getting seasick for the first time. Fortunately, unlike many of my shipmates, I didn't succumb.


We saw many interesting birds on that trip but I was especially impressed with two species. Several flocks of mostly white Northern phalaropes, delicate little shorebirds hardly bigger than sparrows, flew around us like snow squalls. They seemed completely out of their element here not even within sight of land.


The other species, the sooty shearwater, was just the opposite. These birds were clearly in their element.


Sooty Shearwater Photo by Angus Wilson


The sooty shearwater is a big bird. It weighs more than a wood duck and when it sits on the water it looks a little like a duck. But that is where the similarity ends. You don't often see these birds sitting on the ocean surface.


Sooty Shearwater Photo by Angus Wilson


Instead I watched them sailing on their long narrow wings close to the ocean surface. In doing so this otherwise dingy brown (the source of its sooty given name) bird becomes quite beautiful. It earns its surname, shearwater, by the way it tips a wing end down to trail within inches of the sea surface. It takes full advantage of wind gusts and wave crests, scarcely moving those wings. I know of no bird more graceful.


While other birders were attracted by gannets, laughing gulls, dovekies and a razorbill, I remained captured by those shearwaters. I watched them for hours and, if I were to go back today, I would do so again.


It turns out that the sooty shearwater is a bird in the news today. Here's why.


One ornithological fact long known by the general public as well as ornithologists is that the Arctic tern's 22,000 mile migration holds the distance record for birds. One website calls this species the World Champion of Migration. That route takes the tern from its breeding grounds in eastern Canada and Maine across to Europe, down along the coast of Africa to its wintering region in the Antarctic and back up to North America, this time often following the coast of South America.


Ah, but sometimes long-held "facts" turn out not to be true. An eleven member team of ornithologists, five from the United States, five from New Zealand and one from France, headed by Scott Shaffer of the University of California at Santa Cruz, studied the migration of the sooty shearwater.


They did so by attaching tiny devices called archival tags to 33 shearwaters on their breeding grounds in New Zealand. These tags transmit information not only about the location of the individual birds but also about how far under the ocean surface they dive to feed.


What they found was quite amazing. These shearwaters all migrated more than 33,700 miles, with an average distance of just under 40,000 miles and a maximum of almost 46,000 miles. Thus these sooty shearwaters not only outdid the old Arctic tern record of 22,000 miles, but in some cases they more than doubled that record.


We have then a new World Champion of Migration: the sooty shearwater.


Be sure you understand: this migration distance does not include the wanderings of these seabirds on their breeding or wintering grounds. It includes only their 200 days actually migrating.


The route the birds followed varied but generally formed a figure eight in the Pacific Ocean. In early April they left their New Zealand breeding grounds, headed due east toward South America, then turned northwest to their offshore wintering area between North America and Asia at the latitude of the United States and Canada. Finally, they headed south again to complete their trip.


These researchers also found that the tagged shearwaters dove to amazing depths: some more than 200 feet.-- Gerry Rising