Little Troublemaker - Cuckoo Invasion
At this time of year, we’re just about hearing the last of the unmistakeable haunting cry of the Channel-billed Cuckoo, a strangled gargling call which seems to carry for kilometres.
Although they are not strictly nocturnal birds, their all night calling during the breeding season keeps everyone awake! But their chicks have now fledged and breeding has finished for the year, so it’s time for these migratory birds to leave Australia for the warmer climes of New Guinea and Indonesia.
These magnificent birds are amongst the largest of the non-water birds, reaching lengths of 60cm. They cartoon-like appearance, is defined by the huge, pale coloured, downwardly curved bill - you’d think a toucan had escaped from the zoo! Easy to identify in flight, the long tail and wings give the bird a crucifix-shaped silhouette.
In the past decade or so, they have become increasingly common in our cities. But, before you gasp in horror at the thought of more sleepless nights, consider that the Channel-billed Cuckoo does have an upside. It lays its eggs in the nest of the Pied Currawong, which despite being a native, is also a major predator of smaller, rarer native birds such as Fairy Wrens and Silvereyes.
During breeding season, the chicks and eggs of small birds become a major part of the Currawong diet. One study showed that a pair of nesting currawongs destroyed about 40 broods of other native birds to raise one brood of its own.
But as currawong numbers increase, so do the Channel-billed Cuckoos. Unlike many other cuckoos, the young birds do not evict the host's young or eggs from the nest, but simply grow faster and demand all the food, thus starving the Currawong chicks. It may be that by having more Cuckoos around, some of the damage that Pied Currawongs are wreaking on our smaller, more timid native birds will be offset.