Shearwaters are medium-sized long-winged seabirds in the petrel family Procellariidae. They have a global marine distribution, but are most common in temperate and cold waters, and are pelagic outside the breeding season.

Description

These tubenose birds fly with stiff wings and use a "shearing" flight technique (flying very close to the water and seemingly cutting or "shearing" the tips of waves) to move across wave fronts with the minimum of active flight. This technique gives the group its English name. Some small species like the Manx shearwater are cruciform in flight, with their long wings held directly out from their bodies.

Behaviour

Movements

Many shearwaters are long-distance migrants, perhaps most spectacularly sooty shearwaters, which cover distances in excess of from their breeding colonies on the Falkland Islands (52°S 60°W) to as far as 70° north latitude in the North Atlantic Ocean off northern Norway, and around New Zealand to as far as 60° north latitude in the North Pacific Ocean off Alaska. A 2006 study found individual tagged sooty shearwaters from New Zealand migrating a year,

Breeding

Shearwaters come to islands and coastal cliffs only to breed. They are nocturnal at the colonial breeding sites, preferring moonless nights to minimize predation. They nest in burrows and often give eerie contact calls on their night-time visits. They lay a single white egg. The chicks of some species, notably short-tailed and sooty shearwaters, are subject to harvesting from their nest burrows for food, a practice known as muttonbirding, in Australia and New Zealand.

Feeding

Shearwaters feed on fish, squid, and similar oceanic food. Some will follow fishing boats to take scraps, commonly the sooty shearwater; these species also commonly follow whales to feed on fish disturbed by them. Their primary feeding technique is diving, with some species diving to depths of .

Taxonomy

There are about 30 species: a few larger ones in the genera Calonectris and Ardenna and many smaller ones in Puffinus. Recent genomic studies show that Shearwaters form a clade with Procellaria, Bulweria and Pseudobulweria. This arrangement contrasts with earlier conceptions based on mitochondrial DNA sequencing.

  • Puffinus
  • Christmas shearwater Puffinus nativitatis
  • Manx shearwater Puffinus puffinus
  • Yelkouan shearwater Puffinus yelkouan
  • Balearic shearwater Puffinus mauretanicus (proposed lump with P. yelkouan)
  • Bryan's shearwater Puffinus bryani – first described in 2011
  • Black-vented shearwater Puffinus opisthomelas
  • Townsend's shearwater Puffinus auricularis
  • Newell's shearwater Puffinus newelli (split from Townsend's shearwater)
  • Rapa shearwater Puffinus myrtae (split from Newell's shearwater)
  • Fluttering shearwater Puffinus gavia
  • Hutton's shearwater Puffinus huttoni
  • Sargasso shearwater (formerly Audubon's shearwater, before splitting) Puffinus lherminieri
  • Persian shearwater Puffinus persicus (split from Audubon's shearwater)
  • Tropical shearwater Puffinus bailloni (split from Audubon's shearwater)
  • Galápagos shearwater Puffinus subalaris (split from Audubon's shearwater)
  • Bannerman's shearwater Puffinus bannermani
  • Heinroth's shearwater Puffinus heinrothi
  • Little shearwater Puffinus assimilis
  • Subantarctic shearwater Puffinus elegans (split from little shearwater)
  • Barolo shearwater or Macronesian shearwater Puffinus baroli
  • Boyd's shearwater Puffinus boydi (split from Barolo shearwater)
  • Calonectris
  • Streaked shearwater Calonectris leucomelas
  • Scopoli's shearwater Calonectris diomedea (split from Cory's shearwater)
  • Cory's shearwater Calonectris diomedea
  • Cape Verde shearwater Calonectris edwardsii
  • Ardenna
  • Wedge-tailed shearwater Ardenna pacifica
  • Buller's shearwater Ardenna bulleri
  • Sooty shearwater Ardenna grisea
  • Short-tailed shearwater Ardenna tenuirostris
  • Pink-footed shearwater Ardenna creatopus
  • Flesh-footed shearwater Ardenna carneipes
  • Great shearwater Ardenna gravis

There are two extinct species that have been described from fossils.

  • † Lava shearwater or Olson's shearwater Puffinus olsoni
  • † Dune shearwater or Hole's shearwater Puffinus holeae

Phylogeny

Phylogeny of the shearwaters based on a study by Joan Ferrer Obiol and collaborators published in 2022. Only 14 of the 21 recognised species in the genus Puffinus were included.

References

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  • Shearwater videos at the Macauley Library