A small bird, appeared to be wounded and couldn't fly, was found onboard a ship in Southern Atlantic Ocean near Cape Horn (the southest part of South America). I checked against the Book "Birds of Patagonia, Tierra del Fuego & Antartic Peninsula; The Falkland Islands & South Georgia." by E. Couve & C. Vidal with an attempt to ascertaining its ID but in vain. Its white triangle-shaped patch on neck sides and ear-coverts matches the description of Manx Shearwater, but its look does not match with the photo in the book. It also looks like a Little Shearwater or a Common Diving-Petrel (but upper parts should be black instead of grey) too. Could anyone advise the ID of this bird, please? Thanks.