Similar to the Mediterranean Shearwater, the Great Shearwater is distinguished by the well-defined cap on the head, an almost white collar, and a distinctive V-shaped white patch at the base of the tail.
The side of the wing is white, bordered with dark brown, and the flanks have brown spots. During the moult, the Great Shearwater has an irregular white streak down the whole length of the wing. The dark-brown upperside contrasts with the white underside, which has a dark ventral patch.
The Great Shearwater can glide for hours without any apparent effort or beating of its wings, and its planing flight is synchronized with the movement of the waves. Sometimes it patters on the surface, supported by its extended wings, although it has to beat its wings fast in calm weather.
The Great Shearwater constantly alights and goes off again, suddenly stoops before hitting the water violently with its breast, dives, and swims underwater, aided by its wings, before returning to the surface with its prey.
Taking flight from the water can be difficult, but they wander in search of cephalopods floating on the surface or small fish once in flight.
The Great Shearwater can be seen in large flocks around fishing grounds where they surround the ships, fighting for scraps of fish offal thrown into the sea. They can also be seen accompanying whales in search of a meal.
While they are usually silent at sea, they can be extremely noisy when food is on offer.
Great Shearwaters only nest on the Tristan da Cunha group of Islands where there are a few million. In May or June, they fly north along the eastern coasts of North America, where they winter in the North Atlantic, as far north as Iceland.
In August and September, they return south and can be seen passing along the French and British coasts until November.
They are not only found far out to sea but can also be seen within a few kilometres of the coast, and you can sometimes see them from land.