In Anglo-Danish myths a witch named Krake (Crow) was the daughter of the Valkyrie Brunnhilde. Krake was a shape-shifter and could transform herself into a beautiful virgin or a hag or a monster or a crow.
Dreaming of crows can symbolize a sudden change in life, or perhaps death.
Native American Spirituality gives the crow this measure:
As a child I remember my Aunt telling me this poem for the omens associated with the number of crows seen at a time.
One is for bad news, Two is for mirth.
Three is a wedding, Four is a birth.
Five is for riches, Six is a thief.
Seven is a journey, Eight is for grief.
Nine is a secret, Ten is for sorrow.
Eleven is for love, Twelve for joy tomorrow.
A single crow is interpreted by some as the foretelling of ill health.