Shearwaters are associated in folklore with death. This undoubtedly comes from their eeirie cooing nocturnal cry like a cackling witch from the underworld.

This Isle of Man web on the Manx Shearwater (Puffinus puffinus) notes:

“A description of their voice on The Isle of Man, in 1731 says this: “The spirit which haunted the coasts have originated in this noise. , described as infernal. The disturbed spirit of a person shipwrecked on a rock adjacent to this coast wanders about it still, and sometimes makes so terrible a yelling that it is heard at an incredible distance. They tell you that houses even shake with it; and that, not only mankind, but all the brute creation within hearing, tremble at the sound. But what serves very much to increase the shock is that, whenever it makes this extraordinary noise, it is a sure prediction of an approaching storm. . . . At other times the spirit cries out only, ” Hoa, hoa, hoa !” with a voice little, if anything, louder than a human one.”

Richard Dawkins cites the Manx Shearwater on page 87 of his book The God Delusion.

One of the cleverer and more mature of my undergraduate contemporaries, who was deeply religious, went camping in the Scottish isles. In the middle of the night he and his girlfriend were woken in their tent by the voice of the devil, Satan himself; there could be no possible doubt: the voice was in every sense diabolical. My friend would never forget this horrifying experience, and it was one of the factors that later drove him to be ordained. My youthful self was impressed by this story, and recounted it to a gathering of zoologists relaxing in the Rose and Crown Inn, Oxford. Two of them happened to be experienced ornithologists, and they roared with laughter. ‘Manx Shearwater!’ they shouted in delighted chorus. One of them added that the diabolical shrieks and cackles of this species have earned it, in various parts of the world and various languages, the local nickname ‘Devil Bird’.

Around the web

• Manx Shearwater – Wikipedia (above image)
• The RSPB: Manx shearwater
• Manx Shearwater Fact Sheet | Wildlife Trust of Wales

Folklore about shearwaters elsewhere in the world

• In Turkey it was believed that the Dusky Shearwaters which daily travel in mysterious flocks up and down the Bosphorus were animated by condemned human souls. Read here
• Aboard French ships in the nineteenth century both storm petrels and shearwaters were known as âmes damnées (“souls of the damned”), the subtext being that, like some ghosts, part of their punishment after death was to continue to haunt the earth. Muslim seafarers in the nineteenth century similarly said that the Manx and Mediterranean shearwaters (Puffinus puffinus and Puffinus yelkouan) of the eastern Mediterranean were inhabited by damned souls, a belief possibly suggested by their dark plumage. Read here