Recent proposals for a new taxonomy for "Madeiran" Strom-Petrel Oceanodroma castro, based on DNA, morphology, and vocalization into 4 taxa (Friesen et al. 2007, Robb et al. 2008) : Grant´s Storm Petrel, in the Macaronesian Islands, except Cape Verde, including Berlengas; Madeiran Storm-Petrel in Canaries and Madeira; Monteiros Storm-Petrel in the Azores and Cape verde Storm-Petrel in Cape Verde.
The bird seen off Cascais seemed fresh with no active moult on flight feathers by late August, though possibly indicating a winter breeding bird from the Macaronesian Islands, most probably from the Berlengas colony close by.
After 1 or 2 hours using "eau du chum" at Monte dos Ursos bank, 1 ind. came by only to be seen by brief minutes....
shallow fork on tail in some angles but it gives an impression of a square ended tail most of times
narrow rump patch and dull upperwing covert bars.....
long and angular wings....and very diferent travelling/foraging flight from the Wilsons nearby, Madeiran/Grants make very long and fast glides when compared with the more busy flight of Wilsons
At the 2nd stop point around the 13 NM, Corys and great shearwaters were clearly more abundant...
Great Shearwater Puffinus gravis, one of the few seen mostly between 9 and 13 NM