Nature News

Catch shearwaters before they migrate south

by Sue Pike the York Weekly/Portsmouth Herald/Foster's Daily
Greater shearwater  Photo by Sue Pike
While in college in the early 1980s, I spent a summer out a the Isles of Shoals taking the Field Marine Research class. It was a great course, we helped band birds, studied tide pools, scuba-dived in the cold Atlantic water and learned about the raucous gull colonies that made walking on some parts of the island a perilous venture. One of my favorite things was a whale watch - I had never been on one. This was a long time ago, but two things stand out crystal clear in my memory of that trip: the humpback whales feeding, breaching and diving right next to the boat and the shearwaters flying low over the waves.
The whales were certainly awe-inspiring, but I have to say that the shearwaters captured my imagination more than any animal I have ever seen. I love the way they fly. According to the Merriam-Webster dictionary the term “shearwater” refers to “any of numerous oceanic birds (especially genus Puffinus) that are related to the petrels and usually skim close to the waves in flight.” They glide, stiff-winged, over the water, banking (shearing) so that their wingtips seem to graze the surface of the waves.
Shearwaters mobbing humpback photo by  Sue Pike
I went out on my second whale watch just last week. This year is a great whale-watching year, if you haven’t taken one of these trips, it isn’t too late, and while there is no guarantee that you’ll see anything your chance of seeing humpback whales feeding is very high. We saw humpbacks feeding just like I remembered and along with the humpbacks were all sorts of gulls and shearwaters. The whales force lots of tiny fish (mostly sand lance) to the surface while feeding - the birds know this and follow the whales around taking advantage of the bounty.
Another reason I love these birds is because they are in that exotic (to me) group of birds that have tubenoses (these include albatrosses and petrels). The tubes (scientifically known as naricorns) on their upper bill are thought to help these wide-ranging seabirds detect prey; they have a very well-developed sense of smell. They also have a large salt gland that removes excess salt from their blood and secretes it as a salty solution through the tube. It is believed that the length of the tube might be an adaptation that helps direct the salt away from their eyes. One thing the salt gland definitely does is allow tubenoses to drink saltwater directly from the ocean without having to worry about dehydration.
We saw huge greater shearwaters (Puffinus gravis) with wingspans well over three feet swooping in to take advantage of the whales feeding. They’ll either plunge into the water or dive from the surface to catch fish. These shearwaters will be leaving soon to migrate back to their breeding grounds on islands off the coasts of Argentina and South Africa.
Little black and white Manx shearwaters (Puffinus puffinus) darted in. I have read varying accounts of the origin of the name puffin, but one that seems likely is that it is from a Middle English word for the fat offspring of the Manx shearwater, which were thought to be quite tasty. Manx shearwaters are famous for being among the longest-lived wild birds - birds banded in Great Britain have reached the venerable age of 56.
Sooty shearwaters (Puffinus griseus) were also among the throngs of birds surrounding the feeding whales. Sooty shearwaters are the ultra-marathoners of the shearwater family - they nest far south, around Australia, New Zealand and southern South America. One study tagged individuals that migrated nearly 40,000 miles a year, from breeding grounds in New Zealand to summer feeding grounds in the northern Pacific Ocean (Scott Shaffer, Proceedings of the National Academy of Science, 2006).
To see shearwaters around here you generally need to go off-shore - these are birds of the open ocean; they come in close to land only when driven in by storms. It’s nice to know they’re out there, a short boat ride away.

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