Crows have been associated with death and the afterlife in many cultures. However, this isn't always the case, and it's not always a negative connotation.
Crows have long been linked with death probably because they are scavengers and eat the corpses of other animals. In Hinduism, for example, they are believed to be go-betweens from the worlds of the living and the dead, serving as couriers and messengers. There is also a Scottish saying regarding "going away up the Crow Road," which connotes dying.
However, contrary to popular belief, crows do not symbolize death in Native American culture. Instead, they are seen as omens of good luck, with their intelligence being their defining characteristic. This is why they are often portrayed as tricksters in Native American folklore.
In addition, crows have often been associated with war and various gods and goddesses of war. Again, this goes back to death and the crow's dietary habits; a battlefield with dead warriors evokes a sense that scavengers are ready to descend upon the carrion. However, this is part of a natural cycle. Crows clean up what everyone else leaves behind.
Yet another symbolism of the crow comes from ancient Egypt. In this society, they were regarded as icons of loyalty, because of their monogamous nature.