Leucistic Cory’s Shearwater Calonectris borealis off São Miguel, Azores, in November 2019
* Correspondence author. Email: email@example.com
1Futurismo Azores Whale Watching, Portas do Mar, Shop 26, 9500-771, Ponta Delgada, São Miguel Island, Azores, Portugal;
2Wageningen Marine Research, Ankerpark 27, NL-1781 AG Den Helder, The Netherlands
The Cory’s Shearwater Calonectris borealis is the most abundant seabird in the Azores. It breeds along the coast of all islands and on most islets in the archipelago (Monteiro et al. 1996a). Birds attend colonies and adjacent waters from late February to late October (Monteiro et al. 1996b), when they can be seen daily around most islands. From mid-November to late January most birds have migrated to wintering areas in the tropical and southern Atlantic (Camphuysen & van der Meer 2001; González-Solís et al. 2007).
Aberrant colourations such as albinism, leucism, and melanism have been reported in a wide range of seabird species. One of the aberrant colourations, leucism, is defined as a loss of pigment of entire feathers. A loss of pigmentation may also occur in the legs and bill however, excluding a change in colour of the eyes (van Grouw 2006). This loss of pigmentation, or lack of eumelanin, is due to congenital and heritable failure of pigment-producing melanoblasts to reach some or all areas of the skin (van Grouw 2013). In this note, we document an observation of an aberrantly coloured Cory’s Shearwater in the Azores.
We would like to thank Futurismo Azores Whale Watching for providing the whale watching platform. Comments from Laura González Garcia and Mardik Leopold on a draft improved this note.
First two cases of melanism in Cory’s Shearwater Calonectris diomedea. Marine Ornithology 33: 19−22.
Pelagic distribution, moult and (sub-) specific status of Cory’s Shearwaters Calonectris [d.] diomedea/borealis wintering off southern Africa. Marine Ornithology 29: 89–96.
Trans-equatorial migration and mixing in the wintering areas of a pelagic seabird. Frontiers in Ecology and the Environment 5: 297–301.
Not every white bird is an albino: sense and nonsense about colour aberrations in birds. Dutch Birding 28: 79–89.
What colour is that bird? British Birds 106: 17–29.
Notes on colour aberrations in Common Guillemot Uria aalge and Northern Gannet Morus bassanus. Seabird 24: 33–41.
Meer zeevogels met kleurafwijkingen. Nieuwsbrief Nederlandse Zeevogelgroep 5: 2–3.
Past and present status and conservation of the seabirds breeding in the Azores. Biological Conservation 78: 319–328.
Movements, morphology, breeding, molt, diet and feeding of seabirds in the Azores. Colonial Waterbirds 19: 82–97.
Albinistic cases in adult and juvenile Cory’s shearwaters Calonectris diomed/ea. Avocetta 28: 31–32.