mesoplodon's Identifications

This adult male bird had been observed (on what appears to be a nesting site) for several weeks but, most unfortunately, has been sitting on what appears to be another adult, dead, bird, presumably its mate (see photo 4). Very sad as I believe only one other pair has been observed nesting on Pitt Island (see observation posted by me immediately following this one).
Such behaviour has probably only rarely, if ever, been observed before because, presumably, it would be unusual for an adult bird to die on land at a nesting site.