Cooing
Srimad-Bhagavatam
SB Canto 4
SB 4.25.19, Translation:
In such an atmosphere even the animals of the forest became nonviolent and nonenvious like great sages. Consequently, the animals did not attack anyone. Over and above everything was the cooing of the cuckoos. Any passenger passing along that path was invited by that atmosphere to take rest in that nice garden.