Soon after Chinese New Year, a strange, plaintive call echoes through Hong Kong. It insistently rises in pitch, reaching a crescendo before stopping abruptly. The culprit? The Asian koel, Eudynamys scolopaceus, a large cuckoo whose native habitat spans nearly the whole of South and Southeast Asia. In Hong Kong, its mating season—the time of year when males call out in search of partners—coincides with the change in weather, when cotton trees bloom and flame trees erupt in a crimson inferno.
“It’s a reminder of spring,” says James Kwok, assistant education officer at the Hong Kong Birdwatching Society. “It starts in February and goes until July. It’s quite an interesting song – and very loud.”
Asian koels are very common, and they live in Hong Kong year-round, but they are usually only heard during their mating season. The sound they make is so distinctive, it inspired their onomatopoeic name, which is similar across a number of different languages – koyal in Hindi, cou3 gyun1 (噪鵑) in Cantonese. “They make a lot of noise,” says wildlife photographer Robert Ferguson, author of Wild Creatures in Hong Kong. “Here in Sha Kok Mei, in Sai Kung, we are just starting to hear one male, who has moved from near the football pitch to just near our house. So far his loud calls have been in the afternoon, but normally they are every morning, starting before the sunrise.”
It’s a reminder of spring. It’s quite an interesting song – and very loud.
Ferguson says he likes the birds, which are a “soothing reminder” of the days when the chilly northern monsoon gives way to warmer, more humid weather. But others find their cries unbearable. In 2010, the South China Morning Post reported that the Birdwatching Society received a record number of complaints about noisy koels. (It’s unclear what the complainants expected the society to do about them.) In Australia, a similar species of koel is considered a nuisance and Ferguson says some local councils send out trucks to spray trees with water in order to chase the birds away.
That isn’t the case in India, where the birds are celebrated in song and poetry. A. Shrikumar, a columnist for The Hindu, describes them as “the most romanticised bird in literature” and “the muse of great poets and writers” thanks to their association with the monsoon rains.
Chinese poets seem not to have taken as much to koels. But they are still an unmistakable part of the landscape, even if their piercing song is more obvious than the birds themselves. Look closely at the branches of tall trees and you can easily spot them: black males and mottled brown females, both with startling crimson eyes.
“They can be found in the urban areas as well as the countryside,” says Kwok. For birdwatchers, the most remarkable thing about them is their behaviour: like other cuckoos, they are brood parasites, which means they lay their eggs in the nests of other birds. “Other species do the parents’ job for them,” says Kwok.
There is one thing that birdwatchers particularly like about koels, though. Just as their call heralds the arrival of spring, it is also a harbinger of the migratory season, when all manners of exotic birds flock to Hong Kong on their annual journey from south to north. “In terms of biodiversity, Hong Kong is quite high, because we are an important stopover in the Asian-Australasian flyway,” says Kwok. “But most people in Hong Kong don’t recognise that there are so many different birds around them.
What they do know is that, when they hear the Asian koel’s lonely cry, it means the days of mild weather are numbered: summer heat is just around the corner.
Photos in slider: by Dunstan Fernando via Flickr, Robert Ferguson Hong Kong and Wich’yanan Limparungpatthanakij via eBird.