The mournful, descending trill of a fan-tailed cuckoo rang out across the Waterworks Valley signalling that winter was finally in its death throes.
The cuckoo was a little early – August 15 to be precise – but northerly warm winds had clearly carried the first of the migrants from the mainland.
Although the swallow is the traditional harbinger of spring, I always time my seasons by the arrival or departure of two other species, more often heard than seen. These are the fan-tailed cuckoo and another early visitor, the striated pardalote.
Last year it was the pardalotes making an appearance first, in the last week of August. This year favourable winds brought the cuckoos first.
I’m always surprised by the August arrival of the cuckoos because, unlike other species, they do not have to be in a rush to choose, declare and then defend the best breeding sites.
The four species of cuckoos to visit Tasmania in the summer rely on other birds to rear their young, and so do not have to be bothered with the task of building nests once territories with available food close by have been found.
The males merely have to broadcast for a mate and the fan-tailed cuckoo singing in the Waterworks Reserve was certainly doing that, throwing out his voice from the highest perches in the blue gums surrounding the reserve’s twin lakes.
The fan-tailed cuckoo’s song is one of the most familiar sounds of summer, especially as the male birds often sing well past sunset and into the night.
For other birds, the fan-tailed can be viewed as especially problematic – dare I say heartless – because out of the other cuckoo species it exploits the greatest range of host. Its bigger cousin, the pallid cuckoo, generally targets the large open nests of honeyeaters, whistlers and shrike-thrushes, while the two smallest of the four visitors, the shining and the horsfield’s bronze-cuckoos, can squeeze into the roofed and domed nests of ground-nesting birds like the tiny superb fairy-wren. The fan-tailed cuckoo, however, which is about the size of a blackbird, can exploit a whole gamut of nests, including the domed ones and those suspended in shrub and tree.
When a nest has been located, the female cuckoo merely watches and waits for the hosts to fly off to feed. She then slips in to lay her solitary egg. Once it has hatched, the fast-growing cuckoo chick ousts the other chicks from the nest, or merely suffocates them under its larger bulk.
All the while it demands food and, after the chick leaves the nest, there’s no sadder sight in nature than seeing exhausted birds flying to a throw to feed “offspring” two or three times their size.
The fan-tailed cuckoo might have a beautiful song, evocative of the long days of summer, but I greeted it with mixed feelings when I heard it on that sunny mid-winter day. I should have been grateful that a particularly brutal winter now seemed past. Instead, I was thinking of all the pain and chaos the cuckoos will bring to the woods during spring and summer.