Mourners often imagine the loved one materialzing on high, from back of beyond, looking down as a saintly guardian. Sometimes one even seems to become the lost person, playing both roles Grieving birds do that too. Canada Geese mate for life, with the male singing one part of their song, the female the other. After a mate dies, the survivor sings both parts to keep the whole song alive. If humans did that, we would call it romantic.
Diane Ackerman (An Alchemy of Mind)