Alternative name: Greater Shearwater
- Ardenna gravis
Length 43-51 cm, wingspan 100-118 cm, weight 715-950 g
Grey-brown upper parts with dark cap, U-shaped white band at base of tail. Wings mosty white underneath, but with dark edges, and a narrow dark diagonal band near the base visible at close range. White of underside extends up sides of neck, sometimes across nape, but only down to mid-belly; lower belly and under-tail coverts dusky brown. Thin dark bill.
Cory's Shearwater is about the same size with heavier yellow bill, dark head, clean white underwing, and blunt broad wings.
Manx Shearwater is much smaller with no white collar, no white tail band, totally white belly and undertail coverts, and much more blackish.
Audubon's Shearwater is much smaller with short stubby wings, no white collar, no white tail band, long tail, dark undertail coverts, and white spot near eye.
Immature Northern Gannets are superficially similar in plumage pattern, but much larger, and with different flight style.
Atlantic Ocean from Cape Horn northward to southernmost Greenland. Annual migration completes a loop from the eastern seaboard of South and then North America before crossing the Atlantic in August. It can be quite common off the south-western coasts of Great Britain and Ireland before flying south along the eastern side of the Atlantic upon the approach of the northern winter.
Pelagic - open ocean, more likely in the Atlantic than other oceans. Breeds primarily on Nightingale Island, Inaccessible Island, Tristan da Cunha, and Gough Island; small numbers also breed on the Falkland Islands.
A gregarious species, it can often be seen in large numbers from ships or headlands.
Feeds on fish and squid, which it catches from the surface or by plunge-diving. It readily follows feeding whales and fishing boats, where it engages in noisy competition for spoils.
Lays one white egg in a small burrow or in the open grass, which it visits only at night to avoid predation by large gulls.
Call: A piercing eeyah usually given when resting in groups on the water.
- Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood. 2015. The eBird/Clements checklist of birds of the world: v2015, with updates to August 2015. Downloaded from http://www.birds.cornell.edu/clementschecklist/download/
- BirdForum Opus contributors. (2021) Great Shearwater. In: BirdForum, the forum for wild birds and birding. Retrieved 25 October 2021 from https://www.birdforum.net/opus/Great_Shearwater