The Scopoli Shearwater (Calonectris diomedea) breeds on various islands in the Mediterranean Sea.
It is a large brownish shearwater with mostly white underparts and rather large pale bill.
Its Atlantic version is called Cory's Shearwater (Calonectris borealis).
Until around 2012, they were considered two subspecies.

1st photo: Aegean Sea between Patmos and Mykonos, Greece, 25 September 2012
2nd, 3rd & 4th photo: Aegean Sea near Athens, Greece, 28 September 2012