Cory's Shearwater

Photo by charelli
Azores

Includes Scopoli's Shearwater

Calonectris diomedea

Identification

Length 18" (46 cm), wingspan 44-46" (112-117 cm).
Light brown upper parts, white below, yellow bill, 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.

Similar Species

Photo by Glen Tepke
Atlantic southeast of Hatteras, North Carolina, USA, August 2008

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 no white collar, no white tail band, totally white belly and undertail coverts, and much more blackish.
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.

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.

Taxonomy

"Scopoli's Shearwater" subspecies diomedea
Photo by stu78
Kos, Greece, June 2009

Subspecies^[1]

• C. d. diomedea - (Scopoli's):

• Breeds Mediterranean islands

• C. d. borealis - (borealis):

• Breeds Azores, Madeira, Canary Islands and Berlenga islands

Some authorities have split these into two species^[2]

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. Avibase
3. Wikipedia
4. Collins Bird Guide ISBN 0 00 219728 6

• List of references

Recommended Citation

• BirdForum Opus contributors. (2024) Cory's Shearwater. In: BirdForum, the forum for wild birds and birding. Retrieved 3 May 2024 from https://www.birdforum.net/opus/Cory%27s_Shearwater

External Links

Search for photos of Cory's Shearwater in the gallery