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Difference between revisions of "Cory's Shearwater" - BirdForum Opus

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[[Image:Corys_Shearwater.jpg|thumb|550px|right|Photo by {{user|charelli|charelli}}<br />[[Azores]] ]]
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[[Image:Corys_Shearwater.jpg|thumb|550px|right|Cory's Shearwater (subspecies ''C. d. borealis'')<br>Photo by {{user|charelli|charelli}}<br />[[Azores]] ]]
 
'''Includes Scopoli's Shearwater'''
 
'''Includes Scopoli's Shearwater'''
 
;[[:Category:Calonectris|Calonectris]] diomedea
 
;[[:Category:Calonectris|Calonectris]] diomedea
 
==Identification==
 
==Identification==
Length 18" (46 cm), wingspan 44-46" (112-117 cm). <br />
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''C. d. diomedea'' (Scopoli's Shearwater): Length 45-52 cm, wingspan 112-122 cm, weight 560-730 g. <br>
Light brown upper parts, white below, yellow bill, broad wings held bowed, heavy build, leisurely flight style with fewer wingbeats than other shearwaters.
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''C. d. borealis'' (Cory's Shearwater): Length 50-56 cm, wingspan 118-126 cm, weight 817-956 g.<br>
 +
Light brown upper parts, white below, yellow bill with dark subterminal band, broad wings held bowed, heavy build, leisurely flight style with fewer wingbeats than other shearwaters.
  
'''Variation''': the two subspecies differ slightly in plumage, with ''diomedea'' - (Scopoli's Shearwater) showing a little less black in the hand of the underwing due to white inner webs on the primaries, slightly smaller bill which is a little paler, overall slightly paler; the lesser overall size is not noticeable in the field. The average difference between these two forms is difficult to use because of much individual variation.   
+
'''Variation''': the two subspecies differ slightly in plumage, with ''C. d. diomedea'' showing a little less black in the hand of the underwing due to white inner webs on the primaries, slightly smaller bill which is a little paler, overall slightly paler; the lesser overall size is not noticeable in the field. The average difference between these two forms is difficult to use because of much individual variation.   
 
====Similar Species====
 
====Similar Species====
[[Image:080825 Cory s Shearwater 5260.jpg|thumb|350px|right|Photo by {{user|Glen+Tepke|Glen Tepke}}<br />Atlantic southeast of Hatteras, [[North Carolina]], [[USA]], August 2008 ]]
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[[Image:080825 Cory s Shearwater 5260.jpg|thumb|350px|right|Cory's Shearwater (subspecies ''C. d. borealis'')<br>Photo by {{user|Glen+Tepke|Glen Tepke}}<br />Atlantic southeast of Hatteras, [[North Carolina]], [[USA]], August 2008 ]]
 +
[[Cape Verde Shearwater]] is very similar, but slightly smaller and with a slenderer bill and relatively longer tail.<br>
 
[[Great Shearwater]] is about the same size with darker wings and body, smaller bill is black, narrow straight wings, capped appearance, smudgy brown on belly (sometimes faint), and white collar.<br />
 
[[Great Shearwater]] is about the same size with darker wings and body, smaller bill is black, narrow straight wings, capped appearance, smudgy brown on belly (sometimes faint), and white collar.<br />
[[Manx Shearwater]] is much smaller with no white collar, no white tail band, totally white belly and undertail coverts, and much more blackish.<br />
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[[Manx Shearwater]] is much smaller with blacker upperparts, and pure white belly and undertail coverts.<br />
[[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. <br />
+
[[Balearic Shearwater]] is much smaller with browner underparts. <br />
  
 
==Distribution==
 
==Distribution==
Breeds in Atlantic islands south of ca 40 dg N, on islands in the Mediterranean Sea, and on the coast in [[Iberia]]. Post-breeding dispersal takes especially birds of subspecies ''borealis'' north of the breeding range, for example to northern [[Europe]] and to western Atlantic. Winter is spent at sea, most birds migrate to the south Atlantic.  
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Breeds on Atlantic islands between 28°N and 40°N, on the coast in [[Iberia]], and on islands in the Mediterranean Sea. Post-breeding dispersal takes especially birds of subspecies ''borealis'' north of the breeding range, for example to northern [[Europe]] and to western Atlantic. Winter is spent at sea, most birds migrate to the south Atlantic and the southwest Indian Ocean.  
 
==Taxonomy==
 
==Taxonomy==
[[Image:Corys_shearwater_Scopoli_by_stu78.JPG|thumb|350px|right|"Scopoli's Shearwater" subspecies ''diomedea''<br /> Photo by {{user|stu78|stu78}}<br />Kos, [[Greece]], June 2009 ]]
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[[Image:Corys_shearwater_Scopoli_by_stu78.JPG|thumb|350px|right|Scopoli's Shearwater (subspecies ''C. d. diomedea'')<br /> Photo by {{user|stu78|stu78}}<br />Kos, [[Greece]], June 2009 ]]
====Subspecies<sup>[[#References|[1]]]</sup>====
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[[Cape Verde Shearwater]] was formerly included in Cory's Shearwater.
 +
====Subspecies====
 +
Two subspecies are accepted by Clements,<sup>[[#References|[1]]]</sup> treated as distinct species by most other authorities.<sup>[[#References|[2]]]</sup><sup>[[#References|[3]]]</sup>
 
*''C. d. diomedea'' - (Scopoli's):
 
*''C. d. diomedea'' - (Scopoli's):
 
:*Breeds Mediterranean islands
 
:*Breeds Mediterranean islands
 
*''C. d. borealis'' - (borealis):
 
*''C. d. borealis'' - (borealis):
:*Breeds [[Azores]], [[Madeira]], [[Canary Islands]] and Berlenga islands
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:*Breeds [[Azores]], [[Madeira]], [[Canary Islands]], and the Berlenga islands off [[Portugal]]
  
Some authorities have split these into two species<sup>[[#References|[2]]]</sup>
 
 
==Habitat==
 
==Habitat==
 
Breeds on rocky islands and steep cliffs.
 
Breeds on rocky islands and steep cliffs.
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''[[Media:Calonectris diomedea (song).mp3|Listen in an external program]]''
 
''[[Media:Calonectris diomedea (song).mp3|Listen in an external program]]''
 
==References==
 
==References==
#{{Ref-Clements6thDec10}}#Avibase
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#{{Ref-Clements6thDec10}}#[http://www.worldbirdnames.org/BOW/loons/ IOC]
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#[http://www.birdlife.org/datazone/sowbsearchresults.php?a=ns&SearchTerms=Calonectris BirdLife International]
 
#Wikipedia
 
#Wikipedia
 
#Collins Bird Guide ISBN 0 00 219728 6
 
#Collins Bird Guide ISBN 0 00 219728 6

Revision as of 17:20, 31 July 2014

Cory's Shearwater (subspecies C. d. borealis)
Photo by charelli
Azores

Includes Scopoli's Shearwater

Calonectris diomedea

Identification

C. d. diomedea (Scopoli's Shearwater): Length 45-52 cm, wingspan 112-122 cm, weight 560-730 g.
C. d. borealis (Cory's Shearwater): Length 50-56 cm, wingspan 118-126 cm, weight 817-956 g.
Light brown upper parts, white below, yellow bill with dark subterminal band, broad wings held bowed, heavy build, leisurely flight style with fewer wingbeats than other shearwaters.

Variation: the two subspecies differ slightly in plumage, with C. d. diomedea showing a little less black in the hand of the underwing due to white inner webs on the primaries, slightly smaller bill which is a little paler, overall slightly paler; the lesser overall size is not noticeable in the field. The average difference between these two forms is difficult to use because of much individual variation.

Similar Species

Cory's Shearwater (subspecies C. d. borealis)
Photo by Glen Tepke
Atlantic southeast of Hatteras, North Carolina, USA, August 2008

Cape Verde Shearwater is very similar, but slightly smaller and with a slenderer bill and relatively longer tail.
Great Shearwater is about the same size with darker wings and body, smaller bill is black, narrow straight wings, capped appearance, smudgy brown on belly (sometimes faint), and white collar.
Manx Shearwater is much smaller with blacker upperparts, and pure white belly and undertail coverts.
Balearic Shearwater is much smaller with browner underparts.

Distribution

Breeds on Atlantic islands between 28°N and 40°N, on the coast in Iberia, and on islands in the Mediterranean Sea. Post-breeding dispersal takes especially birds of subspecies borealis north of the breeding range, for example to northern Europe and to western Atlantic. Winter is spent at sea, most birds migrate to the south Atlantic and the southwest Indian Ocean.

Taxonomy

Scopoli's Shearwater (subspecies C. d. diomedea)
Photo by stu78
Kos, Greece, June 2009

Cape Verde Shearwater was formerly included in Cory's Shearwater.

Subspecies

Two subspecies are accepted by Clements,[1] treated as distinct species by most other authorities.[2][3]

  • C. d. diomedea - (Scopoli's):
  • Breeds Mediterranean islands
  • C. d. borealis - (borealis):

Habitat

Breeds on rocky islands and steep cliffs.

Behaviour

Breeding

Colonial breeders and ground nesters; 1 egg is laid.

Diet

The diet includes molluscs and fish.

Vocalisation

<flashmp3>Calonectris diomedea (song).mp3</flashmp3>
Listen in an external program

References

  1. Clements, JF. 2010. The Clements Checklist of Birds of the World. 6th ed., with updates to December 2010. Ithaca: Cornell Univ. Press. ISBN 978-0801445019. Spreadsheet available at http://www.birds.cornell.edu/clementschecklist/Clements%206.5.xls/view
  2. IOC
  3. BirdLife International
  4. Wikipedia
  5. Collins Bird Guide ISBN 0 00 219728 6

Recommended Citation

External Links

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