Each spring the Channel-billed Cuckoo and the Common Koel fly from their homes in Papua New Guinea and Indonesia to mate in the sub-tropical region of Australia. The arrival of their distinctive calls marks the passing of another year.
The Channel-billed Cuckoo
The Channel-billed Cuckoo is the world’s largest parasitic bird, its wingspan measuring up to 1 metre. The cuckoo is devious in the way it uses other bird species to rear its chicks – by working in pairs the male cuckoo provokes host-birds into chasing it while the female cuckoo slips into the host-nest to lay its eggs. For several months the east coast region is filled with pterodactyl-like calls as the cuckoos apply this breeding strategy. Once the chick hatches it is unwittingly fed by the host-bird until it is strong enough to fly north to Papua New Guinea.
The Common Koel
In contrast to the raucous call of the Channel-billed Cuckoo the Common Koel adds a mournful tone to the soundscape. Folklore states that the arrival of the Koel signals the beginning of the rainy season. In the recording below small drops of rain fall in the background:
The Koel can be heard calling for hours throughout the day and night. Its breeding strategy is similar to the Channel-billed Cuckoo. Once the chick hatches it kicks out other hatchlings and eggs from the nest and is raised by the host-bird before it flies to its Indonesian homeland.
The annual migration of these extremely vocal birds marks the calendar in a way that other events throughout the year do not. This is yet another example of the way in which sound reflects the passage of time.