Shearwaters

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 colony on the Falkland Islands (52°S 60°W) to as far as 70° north latitude in the North Atlantic Ocean off northern Norway. One study found Sooty shearwaters migrating nearly a year, which would give them the longest animal migration ever recorded electronically. Short-tailed shearwaters perform an even longer "figure of eight" loop migration in the Pacific Ocean from Tasmania to as far north as the Arctic Ocean off northwest Alaska. They are long-lived. A Manx shearwater breeding on Copeland Island, Northern Ireland, was (as of 2003/2004) the oldest known wild bird in the world: ringed as an adult (when at least 5 years old) in July 1953, it was retrapped in July 2003, at least 55 years old. Manx shearwaters migrate over to South America in winter, using waters off southern Brazil and Argentina, so this bird had covered a minimum of on migration alone.

Following the tracks of the migratory Yelkouan shearwater has revealed that this species never flies overland, even if it means flying an extra 1'000 km. For instance, during their seasonal migration towards the Black Sea they would circumvent the entire Peloponnese instead of crossing over the 6 km isthmus of Corinth.

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

They 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.

List of species

The group contains 3 genera with 32 species.
* '' Puffinus''
** Christmas shearwater, ''Puffinus nativatis''
** Manx shearwater, ''Puffinus puffinus''
** Yelkouan shearwater, ''Puffinus yelkouan''
** Balearic shearwater, ''Puffinus mauretanicus''
** Bryan's shearwater, ''Puffinus bryani'' – first described in 2011
** Black-vented shearwater, ''Puffinus opisthomelas''
** Townsend's shearwater, ''Puffinus auriculatus''
** 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''
** Audubon's shearwater, ''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 or mutton bird, ''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

{{reflist, refs=

{{cite journal , last1=Bretagnolle , first1=Vincent , last2=Attié , first2=Carole , last3=Pasquet , first3=Eric , year=1998 , title=Cytochrome-''B'' evidence for validity and phylogenetic relationships of ''Pseudobulweria'' and ''Bulweria'' (Procellariidae) , journal=The Auk , doi=10.2307/4089123 , volume=115 , issue=1 , pages=188–195 , url=http://sora.unm.edu/sites/default/files/journals/auk/v115n01/p0188-p0195.pdf , jstor=4089123

{{cite journal , last1=Nunn , first1=Gary B. , last2=Stanley , first2=Scott E. , year=1998 , title= Body Size Effects and Rates of Cytochrome ''b'' Evolution in Tube-Nosed Seabirds , journal=Molecular Biology and Evolution , doi=10.1093/oxfordjournals.molbev.a025864 , pmid=9787440 , volume=15 , issue=10 , pages=1360–1371 , doi-access=free }
Corrigendum
/ref>

{{cite journal , last=Austin , first=Jeremy J. , year=1996 , title=Molecular Phylogenetics of ''Puffinus'' Shearwaters: Preliminary Evidence from Mitochondrial Cytochrome ''b'' Gene Sequences , journal=Molecular Phylogenetics and Evolution , doi=10.1006/mpev.1996.0060 , pmid=8812308 , volume=6 , issue=1 , pages= 77–88

{{cite web, url=http://news.nationalgeographic.com/news/2006/08/060808-bird-migration.html, title=Longest Animal Migration Measured, Bird Flies 40,000 Miles a Year

External links

Shearwater videos
on the Internet Bird Collection

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Seabirds
Bird common names