What is a Banshee?
A Banshee is, according to the majority of the descriptions I have read, is a female spirit who begins to wail if someone is about to die. Some stories have her appearing as a frightening hag, wailing and screeching; whereas others have her in the guise of a beautiful woman of any age. Not every tale has her screeching and wailing, others have her making a noise that sounds something like an owl's moan. The Banshee's wail has even been described as a low singing sound.
It is said that in 1437 King James I of Scotland was approached by a seer who foretold of his death, later on the seer was identified as a Banshee.
In American folklore, so I have read, the Banshee is just described as a ghoul , rather than a sign of misfortune.