My favourite birds like to forage in my backyard. They are highly prized for their singing in South East Asia. They may cost as much as SGD$30000.00 per bird depending on their singing quality. The birds are categorised by classes A, B and C. I am not familiar with the intricacies of this hobby as I don't believe in keeping birds in cages but I think the classes are about the pitch of the bird call. I have learnt to mimic their calls quite closely to the extent that I can imitate the calls of the expensive birds.
When I mimic the calls of the Spotted Doves or the Zebra doves, they will come to the backyard expecting a treat. Sometimes when they arrive and see me, the Zebra doves will make s clicking sound as if they were telling me to feed them.