Great Shearwater

With a global population of roughly 15 million, the Great Shearwater is one of the most abundant seabirds on the planet. Most of them nest on three remote islands in the southern Atlantic Ocean: Tristan de Cunha, Inaccessible, and Gough. Being in the southern hemisphere, they begin nesting in November, with pairs laying a single egg in January in a burrow or in a crevice among rocks. By April or May, both adults and young are ready to leave their breeding colonies for the North Atlantic. They are the most likely shearwater off the coast of New Hampshire during summer and fall, but you need to be far offshore (generally beyond the Isles of Shoals) to see them.

Shearwaters get their name from their flight. Their long thin wings are adapted to capture tiny wind currents and allow for both high maneuverability and minimal flapping. By staying close to the ocean’s surface, they take advantage of the dynamic interface between air and water and can fly long distances while expending minimal energy. They are so close to the water that their wingtips seem to shear through the waves as they fly. Great Shearwaters feed primarily on squid and small fish, which they obtain either from the surface or via short shallow dives.

Because they are often concentrated in a few huge colonies, seabirds like the Great Shearwater are vulnerable to disturbance or predation at nesting sites. So far this has not been a threat to this species, although there is some concern over ongoing harvesting of eggs and chicks for food on the islands where it occurs. More likely threats are those associated with its ocean foraging habitat, including oil spills, plastic pollution, and incidental capture in fishing nets.