Cory's Shearwater Calonectris borealis (Cory, 1881)

Order: Procellariiformes Family: Procellariidae Status: Breeding in Madeira

cory shearwater calonectris borealis

Recommended birdwatching sea trips to watch this seabird

Bird, dolphin and whale watching trip
Zino’s Petrel Pelagic Expedition
Desertas cruise

Cory’s Shearwater Field ID Keys

Shape & Size

Cory's Shearwater is the largest shearwater and the largest seabird that breeds in Madeira archipelago. It has long, broad and slightly rounded wings and its bill is stout to medium-stout, long and with a hooked tip.

cory shearwater calonectris borealis

Colour Pattern

It is a grey-brown seabird with white underparts. It has greyish-brown upperparts, neck sides and head with no marked cap. Its underwings are white with dark remiges and the bill is yellowish.

cory shearwater calonectris borealis

Behavior

Cory's Shearwaters flight is relaxed, low, very close to sea and weaving its body through the waves, rarely beating its wings. Under strong winds it flies higher describing consecutive ‘U’s and when coming lower it seems that it almost touches the surface. In Madeira it is common to hear them after sunset near the coastline all around the island.

cory shearwater calonectris borealis and Bryde's whale Balaenoptera edeni

Habitat

This seabird is very common in the Atlantic, especially in warmer waters as Madeira archipelago, where it is around from end of February to October, during its breeding season. The remaining months of the year are spent offshore in the South Atlantic. Cory’s shearwater can be seen on all islands of the archipelago with Selvagens having the biggest number of birds per square meter.

cory shearwater calonectris borealis

Distinction from similar species

It can easily be confused with Scopoli’s shearwater and only a good and close observation may distinguish both species. Cory’s shearwater is bigger, bulkier, with broader wings and bigger head and bill. The underwing of Cory’s have a larger dark line along the remiges.

cory shearwater calonectris borealis

Calonectris borealis Biometrics

Wingspan: 113 - 124 cm (Howell, 2012)
Total length: 48 - 56 cm (Howell, 2012)
Tail length: 121 - 144 mm (Howell, 2012)
Bill length: 50 - 60 mm (Howell, 2012)
Weight: 700 - 800 g (Hume, 2002)

Other Bird Facts

Seasonality in Madeira: From end of February to early November
Breeding: In Madeira, this species nest mainly in sea cliffs while in Selvagens it builds its nests on holes on the ground or under big rocks, but never too far from the ocean. It lays one egg on the unique annual brood, between May and June. Incubation period is 54 days and the chick fledge by October.
Diet: Feeds on fish and crustaceans and it dives to catch the fish.

cory shearwater calonectris borealis

Status

Madeira local status by Romano et al, 2010: Very common breeding bird
Madeira local status by Zino et al, 1995: Very common breeding bird
Conservation status by the IUCN Red List Categories, 2013: Least Concern ver 3.1

Name of this species in other languages

Portuguese: Cagarra
German: Gelbschnabelsturmtaucher-diomedea
Dutch: Scopoli's Pijlstormvogel
Swedish: Gulnäbbad lira
Danish: Kuhls Skråpe
Finish: Keltanokkaliitäjä
Norwegian: Gulnebblire
Spanish: Pardela cenicienta
French: Puffin cendré
Italian: Berta maggiore
Polish: Burzyk żółtodzioby
Slovak: Víchrovník plavý
Czech: Buřňák šedý

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