The Owlman of Mawnan, Cornwall

Mawnan sits near Falmouth, where the Helford River meets the sea. St Mawnan and St Stephen's Church stands at the end of a mile-long, sheltered, narrow lane, its tower dating from the 14th and 15th centuries. In 1976 the area was already alive with monster talk. Morgawr, the sea serpent of Falmouth Bay, had been reported through 1975 and 1976. At the centre of that wave stood Tony "Doc" Shiels, a local magician, artist and self-described monster-raiser.

Saturday 17 April 1976, Easter weekend. The Melling family from Lancashire were camping on holiday. In one telling, the parents were setting up a picnic while June, 12, and Vicky, 9, wandered into the churchyard. They heard a strange sound from above. They looked up.

Something was hovering over the church tower. A "huge great thing with feathers, like a big man with flapping wings," in the words of a 1976 booklet. A "big, feathered bird-man," in a letter Shiels wrote that April. The girls ran screaming to the car.

Their father, Don Melling, cut the holiday short by three days. A drawing of the creature reached Shiels, but Don Melling would not let the girls be interviewed. They have never given an interview themselves. Shiels named the creature the Owlman.

On 3 July 1976, Sally Chapman and Barbara Perry, both 14, were camping in the woods beside the church. "It was like a big owl with pointed ears, as big as a man," Chapman wrote. "The eyes were red and glowing." At first they took it for someone dressed up, playing a joke. "I laughed at it, we both did, then it went up in the air and we both screamed."

Perry remembered "a nasty owl-face with big ears and big red eyes," grey feathers and black claws. "It just flew straight up and disappeared in the treetops." Shiels interviewed both girls on Grebe Beach the next day. Each drew the creature and wrote a description underneath.

The reports kept coming. In 1978 Miss Opie, 16, described "a monster, like a devil, flying up through the trees near old Mawnan Church." Shiels wrote to Janet and Colin Bord: "The owlman is certainly back in business, it seems." In 1995 an anonymous letter to the Western Morning News called it a "vision from hell." No photograph, film, track or feather has ever surfaced.

The debate that followed centres on Shiels. In Magonia in 2001, Gareth Medway noted that the Owlman "showed himself only to adolescent girls on holiday." Medway found the drawings "remarkably excellent" for a child and saw matching habits in the Chapman and Perry handwriting. By one account, Don Melling accused Shiels of hoaxing his daughters, and Shiels denied it, though he once called himself "a charlatan and a mountebank." Jonathan Downes of the Centre for Fortean Zoology concedes Shiels could have invented the Owlman.

Others look to real birds. Joe Nickell pointed to barn owls nesting in the church tower. A Eurasian eagle-owl has been suggested, and Janet and Colin Bord came to think an escaped aviary bird was likely.

The Owlman appeared the same year John Keel's The Mothman Prophecies came out in Britain, and Medway called it the Mothman's "Cornish counterpart." It has since turned up in Lost Tapes, in the 2013 film Lord of Tears and in Carl Grose's play Horse Piss for Blood. The church tower still guides boats into the Helford River.