Pelagic Distribution, Moult and (sub-)specific Status of Cory's Shearwaters Calonectris [d] Diomedea/borealis Wintering Off Southern Africa
2001; Volume: 29; Issue: 2 Linguagem: Inglês
10.5038/2074-1235.29.2.504
ISSN2074-1235
AutoresC.J. Camphuysen, Jaap van der Meer,
Tópico(s)Marine animal studies overview
ResumoCAMPHUYSEN, C.J. & VAN DER MEER, J. 2001. Pelagic distribution, moult and (sub-)specific status of Cory’s Shearwaters Calonectris [d.] diomedea/borealis wintering off southern Africa. Marine Ornithology 29: 89–96. Newly described field characters are used to separate Cory’s Shearwaters of the east Atlantic population ( Calonectris diomedea borealis, or C. borealis) from those of the Mediterranean population ( C.d. diomedea, or C. diomedea) in their wintering areas off southern Africa. It is shown that borealis outnumbered diomedea in most areas, which contradicts the current consensus that the majority of Cory’s Shearwaters wintering of southern Africa belong to the Mediterranean population. Borealis outnumbered diomedea on average by a factor of 6:1 on the continental shelf, but over deep ocean waters north of 34°S both varieties were equally scarce. In the offshore areas influenced by recently shed Agulhas Rings (39°–34°S), borealis was 10 times more numerous than diomedea, with foraging flocks concentrating at the edges of the rings. Off Cape Town, where borealis predominated, east-/southeastbound migratory movements were observed. Cory’s Shearwaters deployed a variety of feeding techniques and were occasionally attracted to fishing vessels and foraging dolphins. Most birds had nearly finished their primary moult, which is in accordance with expectation for breeding birds that normally complete primary moult around March.
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