When Krsna and all the cowherd boys are in the forest imitating the sounds of animals, it is not that activity in itself that is the source of enjoyment, but it is the exchange within that particular activity between the cowherd boys and Krsna that is the essence. When Krsna and all the cowherd boys are imitating the sounds of all the animals Krsna is enjoying these activities very much. He is especially enjoying it because of sharing it with the cowherd boys...
Krsna is producing the sounds of all the animals in the forest of Vrindavan - it is mentioned in "The Nectar of Devotion" that Krsna is speaking the language of all the animals...
As He is having pastimes with the cowherd boys, He is simultaneously sharing with the animals in the forest.
(Kadmba Kanana Swami, Goloka Dhama 2006)
