Tweet of the Day is the voice of birds and our relationship with them, from around the world.

Liz Bonnin presents the morepork or Ru-Ru, New Zealand's only surviving native owl. Strange double notes in the forests of New Zealand were once thought to be cries from the Underworld. But these calls are most likely to be that of a morepork calling. Its familiar call earned it the alternative Maori name of "ruru". Largely nocturnal, it has brown, streaky feathers and large bright yellow eyes which are well adapted for almost silent night hunting forays for large insects, spiders, small birds and mammals. In Maori mythology, moreporks, or "ruru" are spiritual birds, and can represent the ancestral spirit of a family, taking the form of a woman known as "Hine-Ruru" or "owl woman" who acts as a guardian, protecting and advising the family members.