If it's a Raven or Corbie, it has the symbology of virility or wisdom, however if it's a Crow or Rook then the symbology becomes long life. Either posed Regardant (or Reguardant) (looking backward over left shoulder) is an indication symbolically, of caution and retrospect.
Many other interpretations can be implied depending on background (fields) an that on which the animal is emblazoned, such as a shield. All very subjective and relevant to the country of origin...