I photographed a Bulweria petrel in May 2010 which I identified at the time as Bulwer's.
Now I am beginning to have serious doubts whether the bird was in fact a Jouanin's. I have zero previous experience of either, but the large-headed appearance and at times heavy-looking bill, and long broad wings look more like these pics of Jouanin's than these of Bulwer's.
My brief notes were as follows:
While scanning the stern of the boat for shearwaters, I came across a bird skimming across the waves quite a way back.
At first I took it to be a shearwater, but there were several things 'not right'. The bird was following a zig-zag path back and forth across the wake of the boat, the tail was much too long for Short-tailed Shearwater, the wings were held forward and bent back at the carpal, and the bill was way too thick for a shearwater. Although the bird looked all dark, at times a faint paler bar across the upperwing coverts could be made out.
The bird made its way gradually closer, but veered off and passed us some way to the right, indulging in a bit of 'foot-paddling', when it appeared to take a fish from the water surface.
Attached is a montage of images of the bird. I'd be grateful for any thoughts on its identity, especially from anyone with experience of both species.