- Written by Nadia O’Carroll
This is a large species - length of up to 66cm, weight up to 1 kilogram and 1 metre wingspan. Its plumage is mottled grey on back and wings, pale chest; its long tail is barred. A patch of bare red skin surrounds the eye. It has a massive curved beak that is reminiscent of the appearance of hornbill’s beaks. In flight its long tail and wide wingspan give it a crucifix shaped silhouette, it flies with strong, slow, regular wingbeats.
The Channel-billed cuckoos diet consists mainly of fruit especially figs, seeds, insects and occasionally nestling birds. Its preferred habitat in Australia is tall open forest especially along watercourses and it typically feeds high in the canopy of tall trees. It is a shy and retiring bird, which is more often seen and heard in flight.
Channel-billed Cuckoos are found in Indonesia, Timor, Papua New Guinea and the Bismark Archipelago, there are three sub species, two of which remain resident in these areas. The migratory species flies to northern and eastern Australia to breed, and vagrant birds have been observed as far away as New Zealand and New Caledonia.
The birds arrive in Australia between August and October every year to breed. Not to build a nest and raise their young themselves but to find other birds to do this task on their behalf because Channel-billed Cuckoos are the world’s largest parasitic birds.
During breeding season the birds form pair bonds. Once a suitable host nest has been located the male may distract the host parents while the female Cuckoo slips into the nest to lay her eggs. There are eight species of Australian native birds that the Channel-billed Cuckoos utilise as hosts most often large species such as currawongs, magpies and crows are selected. The Channel-billed Cuckoo nestling does not evict the host’s nestlings; it is able to monopolise food causing the other chicks to starve. Baby cuckoos quickly grow larger than their host parents who sometimes appear rather frightened of their huge surrogate chick. The Cuckoo’s biological parents remain in the area and once the young Cuckoo is out of the nest they begin to call to it. The young bird recognises their call and joins them for the long flight north over the Torres Strait to Papua New Guinea and other islands. The birds leave Australia around February and March.
The Channel-billed Cuckoo like its relative the Common Koel arrives in Australia in spring. Although they are quite shy and secretive birds they have loud raucous calling particularly in flight. Their arrival coincides with the start of summer storms and consequently both these species are often called rainbirds and stormbirds.