I have a pair of wild ravens and a pair of crows that I spend time with, the bolder of the raven pair comes and stands near us and bobs his head, clicks his beak and makes a quiet noise that sounds like a child saying MUM until I give him some food - what is he/she saying really?
I love watching the interaction between them and the crows, but this is something I have only seen him/her do when he is on his own near me.