Cape Verde Shearwater (Calonectris edwardsii)

Taxonomy

The Cape Verde Shearwater was originally treated as a distinct species before being lumped as a race of Cory's Shearwater. There is now a strong move to restore this distinctive form to full species status.
 

Identification

Should be looked for among Cory's Shearwaters along the Atlantic seaboard of North America and in Europe. Identification is reviewed in Porter et al. 1997. The article includes an excellent collection of color photographs of the species taken at sea off Senegal in West Africa. Approximately 10% smaller than Cory's Shearwater, with a less heavy build. Has a slightly darker brown mantle and hindneck, creating a greater degree of contrast between brownish upperparts and whitish underparts. Head darker brown creating a hooded effect. Bill less heavy, gray-horn colored with less contrast between bill shaft and tip (appears uniform gray at distance).
 

Where and When

An endemic breeder to the Cape Verde Islands in the North Atlantic off west Africa. Regularly observed in seas surrounding the islands and off the African mainland in Senegalese waters, where an estimated 10% of the population have been seen during October in the upwelling zone (Hazevoet, 1997). It is unclear whether these birds represent post-breeding adults or adults that are still feeding young. As far as I am aware, not yet recorded in Europe. There is at least one plausible claims from North America (North Carolina) and this species should be looked for carefully. Three shearwaters at 38 deg. 36 min S, 53 deg. 30 min W off Argentina on 18 Feb 1992 considered to be Cape Verde Shearwaters (Curtis, 1994).

Within the Cape Verde Islands, the main colonies are on Brava, Branco and Raso with smaller numbers elsewhere. Population estimates of 10,000 pairs during the 1990's may be optimistic. Local fisherman collect at least 7,500 nestlings each year, presumably a significant stress to the population (Hazevoet et al., 1996).
 

Photos and information on the web

View of upperparts Photo by Tony Marr, from on-line article by Marr, Newell and Porter.
 

Literature

Curtis,W.F. (1994) Further South Atlantic records. Sea Swallow 43: 19-28.

Richard Porter, Dick Newell, Tony Marr and Robin Jolliffe (1997) Identification of Cape Verde Shearwater. Birding World 10(6): p222-228.

Hazevoet, C.J., Fischer, S. and Deloison, G. (1996) Notes on distribution, conservation, and taxonmy of birds from the Cape Verde Islands, including records of six species new to the archiplego. Bulletin Zoologisch Museum, University of Amsterdam, 15(3): 21-27.

Hazevoet, C.J. (1997) Notes on distribution, conservation, and taxonmy of birds from the Cape Verde Islands, including records of six species new to the archiplego. Bulletin Zoologisch Museum, University of Amsterdam, 15(13): 89-100.



Copyright © 2002 All rights reserved. Angus Wilson

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