General
Great Shearwater: Long-winged seabird a bit larger than a Common Gull. Dark grey upperparts and upperwings with pale edging, white uppertail coverts, black tail, grey-brown cap and white collar. Underparts white except for brown vent and brown patch on belly. White wing linings and thin, black bill. Sexes and ages similar. Flies with fairly quick wingbeats followed by glides on rather stiff wings.
Range and Habitat
Great Shearwater: Visitor to the UK. Breeds in south Atlantic, near Falkland Islands. Birds remain offshore, and can be seen primarily from Northern and Western Isles, western Ireland, and Cornish coast. Most likely to be seen in late summer and early autumn.
Breeding and Nesting
Great Shearwater: Breeding is on oceanic island shores in far south of southern hemisphere. Nesting is colonial, with nests built among rocks or in burrows. A single egg is laid, and is and incubated by both parents for an average of 55 days. Both parents care for chick for about 15 weeks.
Foraging and Feeding
Great Shearwater: Feeds on small fish and squid from surface or below water. Also eats crustaceans, fish offal. Hunting techniques include seizing prey on ocean surface, plunge-diving from height of up to 10 meters, and pursuit diving.
Vocalisation
Great Shearwater: Gives a low nasal, squealing call when resting on water.
Similar Species
Great Shearwater: Cory's Shearwater lacks the distinct cap, has a yellow bill, lacks a dark belly patch, and lacks dark markings across the underwing coverts.