Baltimore Pelagic, Co.Cork Ireland 21-08-2021
[order] Procellariiformes | [family] Procellariidae | [latin] Puffinus gravis | [UK] Great Shearwater | [FR] Puffin majeur | [DE] Großer Sturmtaucher | [ES] Pardela Capirotada | [IT] Berta dell'Atlantico | [NL] Grote Pijlstormvogel
Measurements
spanwidth min.: 105 cm
spanwidth max.: 122 cm
size min.: 43 cm
size max.: 51 cm
Breeding
incubation min.: 47 days
incubation max.: 55 days
fledging min.: 53 days
fledging max.: 58 days
broods 1
eggs min.: 1
eggs max.: 1
Physical characteristics
Large shearwater with dark bill with tube on top and dark brown cap. Grayish-brown upperparts with White uppertail coverts White underparts with indistinct brownish belly Rapid wingbeats. Glides on stiff wings
Habitat
Oceanic, in cool to fairly cold pelagic waters of South and North Atlantic, migrating quickly without stopping across intervening tropical and sub-tropical seas, and usually avoiding both mid-ocean and inshore zones, preferring (in non-breeding season) chilly climates, even with scattered icebergs, to sunny, warmer currents sought by Cory's Shearwater Calonectris diomedea. Stops short of Arctic pack-ice, and occupies west Palearctic habitats almost exclusively during third quarter of year, sometimes well into October in east Atlantic. Less frequently inshore, or in narrow seas such as English Channel, than Sooty Shearwater Puffinus griseus. In flight, except at breeding stations, confined to lowest belt of airspace, but less aerial than other shearwaters and more given to resting and feeding for long periods on water, often in rafts, making shallow dives below surface. Indifferent to shipping but will approach fishing vessels for food, or follow whales and porpoises. Unaffected by stormy weather. Sometimes overlaps with other shearwaters, but does not normally associate with them. Breeding habitat in South Atlantic up to c. 400 m on any kind of terrain permitting excavation of burrows, including slopes under tussock grass or woodland
Other details
Puffinus gravis breeds at three main sites: Nightingale and Inaccessible islands in the Tristan da Cunha group, and Gough Island, Tristan da Cunha (to UK) (Snow and Perrins 1998, Carboneras 1992d). This species has a large range, with an estimated global Extent of Occurrence of 52.8 million km2. A minimum of 5,000,000 pairs are thought to breed at Tristan da Cunha, and 600,000 to 3,000,000 pairs at Gough. Birds also breed in small numbers in the Falkland Islands (to UK), where the only confirmed site is Kidney Island (no more than 15 pairs recorded in 1987), though there is a slight possibilty of breeding near Wineglass Hill, East Falkland, where one has been caught. The species has a large global population estimated to be 16,500,000 individuals. Adults begin a transequatorial migration in April, moving north-west to South America, up to Canada, past Greenland and onto the north-east Atlantic before returning south in November to the breeding islands. The species breeds on sloping ground, mainly in areas of tussock grass or Phylica woodland. It feeds mostly on fish, squid and fish offal (attending trawlers, sometimes in large numbers), and also on some crustaceans.
Feeding
Follows and catches surface-feeding fishes, also squids, crustaceans, and small fishes such as sand launces; dives under surface for fishes and rises into air to swallow. Also eats offal from fishing boats and apparently whale feces.
