Is it a bird? Definitely. Is it a vulture? Probably - but nobody is quite sure when or how it made its home in the mountains of Gwynedd.
Photographer Alan Price's picture of the bird in the Nantlle Valley
The bird has been sighted several times in the past few months, most recently above Blaenau Ffestiniog.
Stonemason Keith Williams said his attention was first drawn by the bird's unusual cry.
The Independent Bird Register has had several reports of the bird, but none of a missing vulture to match it.
"We thought it was a heron to begin with, until we heard the noise it was making," said Mr Williams, who was working with fellow stonemason Alun Jones.
"It was much bigger than a heron in both length and breadth - its wing span must have been two metres (6.56ft) across."
Mr Williams said they had seen the bird four to five times near the same place.
"We've had our leg pulled over this, but we've worked outside for years, and it was definitely something out of the ordinary," he added.
The same bird is thought to have been seen in the Nantlle Valley in August and more recently in the Bangor area.
As it happens, to the south - as the vulture flies - lives a similar bird. George from Machynlleth in Powys made headlines in June when he was spotted flying high above the Dyfi valley.
Birds of a feather: George the vulture lives in Machynlleth
But this one is not George, whose owner Barry Macdonald said he had not been allowed to roam in the past couple of weeks because of the windy conditions, and when he flew he did not venture too far north.
"I've had phone calls from people who have seen this other vulture but I don't think any of the sightings could have been of George," he said.
Neil Fowler of the Independent Bird Register has a database of over 51,000 ringed birds, but no reports of a missing vulture which would fit the description of the one in Gwynedd.
"The one which has been seen is a long-billed vulture. It will survive the winter. It does not take live foods but feeds on carrion."
There had been sightings of vultures in Norfolk, Suffolk, London and Devon, said Mr Fowler.
Because the birds travelled vast distances they were difficult to catch, he said.
Vultures were not built to fly very well, but rather soared on a breeze, he added, picking up the smell of a carcass.
They also tended to move south over the winter, so the north Wales vulture could soon make an appearance in mid Wales, he said.