THOSE GWARKY BIRDS

Some moments in nature stick with you—especially when they start with a sound you never quite forget. For David Waterhouse, that sound belongs to one of Australia’s most unmistakable summer visitors: the channel-billed cuckoo. Long before you spot it, you hear it—loud, strange and carrying across the landscape. David has chosen to leave a gift to WWF Australia in his Will, helping ensure that future generations can continue to experience moments like these. We hope you enjoy ‘Those Gwarky Birds’ – personal insights and observations by David Waterhouse – a passionate naturalist, storyteller and WWF supporter – from his experiences in nature.

I heard them before I saw them. In late January, they were slowly winging their way over the ancient volcanic plugs of the Warrumbungle Range in inland New South Wales. Their long, tapered wings and all-grey plumage identified them, even at a distance, as channel-billed cuckoos. Their unforgettable mournful cries seemed to echo amongst the peaks as they lost height and then disappeared into the tree canopy.

In a month’s time, they would be gone. The birds are strictly migratory, spending the winter in eastern Indonesia and New Guinea. In the Top End of Australia, they are known as ‘storm birds’ or ‘rain birds’ because their loud, sad cries seem to herald the arrival of the monsoon floods. In some parts of the country, they are called ‘fig hawks’, due to their fondness for figs, although the ‘fig hawk’ is not a raptor. It is a bona fide cuckoo because, like the bird whose cries of ‘cuck-oo’ were well known to British settlers, it lays its eggs in the nests of other birds, such as currawongs, crows and magpies. They arrive in New South Wales in September but, until a few decades ago, were unknown in the Sydney region. They are becoming more familiar because of their loud, far-carrying calls, even if not many people know what they are called. There are those who are pleased to be rid of the strange birds by late February, or perhaps early March, because they resent the ‘racket’ these cuckoos make, especially if they are awoken in the early hours! Older people who remember the ‘cuckoo-less’ days, sometimes ask why the birds are now commonplace in Sydney during the warmer months. The answer seems to be linked to the presence of pied currawongs, which were once absent from the city during summer. It used to be the case that these birds were only winter visitors to the city too, retreating to the Blue Mountains and beyond in summer. They started to become year-round residents some time before the channel-bills moved into parasitise their nests. Pairs of pied currawongs may well raise offspring if they start to breed in spring, but a second breeding attempt as the weather warms up is likely to be thwarted as the cuckoos choose mates and start searching around for a nest to take over.

I do not know if the male cuckoo or female or indeed both, attack and chase off the currawongs high in the trees. Whatever the case, the hapless currawongs are seen off, and any eggs or young are pushed out of the nest or possibly devoured. The hen cuckoo is then free to lay her own eggs. Once hatched, the young cuckoos, fed frequently by the gullible currawong pair, soon grow. I once saw four or five well-grown youngsters towards summer’s end, almost overflowing the flimsy platform of a nest. They simultaneously stretched out their necks to a returning foster parent, like desperate castaways on a flimsy dinghy. The scene could be fully taken in by an observer because the nest was built on a branch overhanging a bushland path at Limekiln Creek in Oatley. Another summer, in late January, channel-billed cuckoos had taken over a nest in a lofty and thickly-foliaged tallowwood tree in my street. Nothing could be seen of the nest or the birds except when one of the currawong pair flew in or out, but plenty of noise could be heard. One particular morning, the young cuckoos must have been well grown and ready to quit the nests. Out of the blue, quite literally, flew two adult cuckoos from over the rooftops and landed in the top of the tree, accompanied by a lot of racket from all parties. A little time later, to my astonishment, five cuckoos flew out of the tree. The parents had returned to ‘pick up’ their offspring, after having left them for another species to nurture. Looking through the literature, I eventually found a quite recent reference to this surprising phenomenon. It had only been observed by ornithologists in the past few years. As far as I know, no other cuckoos in the world do this. The behaviour of these channel-bills begs the question; how do they know when their young are ready to leave? Perhaps they had paid several visits to the nest, and I happened to have been walking down the street at the right moment. As I stood watching them fly off together, a small girl and her mother passed by. The child heard the cacophony above and said, “Those gwarky birds are there again mummy.” They were indeed. No doubt, in a few days’ time, the family would be departing ever northward for New Guinea. David’s story reflects a lifelong love of the natural world, shaped by years of careful watching and listening. Through his gift in his Will, he’s helping protect wildlife and wild places for future generations. You may wish to consider leaving a gift in your Will too.