The Great Shearwater


Sometime in mid-June, while setting up the lifeguard tower at East Hampton Village’s Main Beach, I noticed two “tubenose” carcasses in the wrack line. Tubenoses are a group of pelagic birds that include the albatrosses, petrels and shearwaters, and they are named for the unusual and prominent paired tubular nostrils located on the aft end of their upper bill. Based on their markings, thin black bills and approximately 40-inch-long wingspans, these were great (aka greater) shearwaters (Puffinus gravis).Many oceanic and brackish-water birds ingest large amounts of salt that their kidneys alone cannot filter out, and they have special glands in the front of their skulls designed to remove excessive salt from their blood. I was surprised to learn that several species of sparrows that reside in brackish marshes fall into this category. In the case of the tubenoses, the salt-removal gland is connected to the prominent tubular nostrils where the salty liquid is excreted, or oozes out.

The sense of smell is not well developed in most birds, but the tubenoses are one of the exceptions to that rule. They can detect oily fish scents from quite a distance at sea, a characteristic that leaders of pelagic birding trips take advantage of by pouring small amounts of fish oil, preferably heated, overboard to attract the out-of-sight tubenoses. Their keen olfactory sense helps them locate food at sea: small fish, squid and crustaceans.

It is unusual to have the opportunity to examine this seafaring bird up close, as it is a species that one generally has to travel offshore by boat to glimpse. Other than its distinctive bill, shearwaters have extremely long, narrow wings. This wing shape is designed to minimize drag, enabling it to glide very efficiently. Much like hawks take advantage of updrafts created by landforms (mountains and ridges), shearwaters can take advantage of the miniscule updrafts created as wind moves up and over even very small waves on the surface of the sea.

Their very efficient wing shape also enables them to glide long distances downwind while losing an almost imperceptible amount of altitude. When they do need to gain some altitude, they simply turn into the wind, rise a few feet above the sea, turn downwind and continue the long glide, all without a flap of the wings.

Great shearwaters have an interesting life history. They only go ashore to nest, and their nesting sites are a handful of tiny islands in the cold waters of the South Atlantic, most found a bit closer to Africa than South America. They arrive at their nesting islands in September.

There they nest in burrows, laying a single egg in mid-November that they incubate for nearly two months and rear the chicks for another three and a half months until they are ready to fly.

That’s over five months from egg laying to fledged young! I’m not sure why they have such a long incubation period and slow growth rate.

In mid-May the young are ready for their first migration: a loop around the Atlantic. First they head north along the western edge of the Atlantic, reaching this area in June and continuing to the waters around Newfoundland. By late summer they are heading south along the eastern Atlantic, reaching their nesting areas in September, the beginning of the spring season in the South Atlantic. One of my references claims that a “lucky” shearwater will make this trip for 60 years, quite a long lifespan for a bird.

Since my initial discovery of the pair of shearwaters at Main Beach, Chris Chapin and Juliana Duryea reported many more dead shearwater birds along our East Hampton beaches. Apparently an estimated 80 shearwaters were found on eastern Long Island ocean beaches last month. Several were still alive but did not survive very long.

NYSDEC’s Wildlife Pathology Unit examined several of the birds and found that they were emaciated yearlings. This is a pattern that has been noted in the recent past. Between 1993 and 2011 there have been 12 separate mortality events involving this species along the eastern seaboard of the United States. A total of 5,000 great shearwaters were recovered, a majority of which were emaciated.

The cause of these mortality events remains unknown.

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