http://www.orkneyjar.com/tradition/hunt.htm
Belief in the Wild Hunt is found throughout the British Isles, as well across Northern Europe.
Although the basic idea is the same in all variations – a phantasmal leader and his men accompanied by hounds who “fly” through the night in pursuit of something.
What they are pursuing is not clear although Norse legend has various objects such as a visionary boar or wild-horse and even magical maidens known as Moss Maidens.
Later Christian influences had them summoning the souls of evildoers and unbaptised infants. Although the tradition is almost certainly Northern European in origin, like all folklore it adapted to fit the area it later became attached to.