When a mate appears to be receptive , the male puffs up the black feathers on the sides of the neck .
It appears like a black collar or ruff and walks towards the female while twisting mate 's body from side to side .
When a mate appears to be receptive , the male puffs up the black feathers on the sides of the neck so that it appears like a black collar or ruff and walks towards the female while twisting his body from side to side .