By Thio Hui Bing.
On 24th December 2017, I went down to Sentosa to see for myself this interesting phenomenon, after friends shared that a particular tree was attracting several species of migrant cuckoos that are usually hard to see. The reason for the attraction was the outbreak of Tussock Moth caterpillars, a favorite food of the cuckoos. The fig tree, Ficus Superba was bare as it had just shed its leaves. The caterpillars were feeding on the new young shoots. It also exposed the nest of resident Crested Goshawks. I am amazed and wonder how the birds know that there is plenty of food here. Is it by experience, by chance while en-route during its migration, by sight or by scent?
The bare Ficus Superba sheds its leaves regularly. The new young shoots is less toxic for the caterpillars.
Many other birders also specially came to see this interesting gathering of cuckoos. It was a cloudy day even until noon. We managed to see the Large Hawk_Cuckoos, Indian Cuckoos and an Asian Emerald Cuckoo, a very rare non breeding visitor. This will be only our second sighting, the first record was in 2006 (Lim Kim Seng, Avifauna of Singapore).
The Tussock moth caterpillars are the reasons why so much cuckoo species are seen here.
Based on my observations that morning, the Large Hawk-Cuckoo and Indian Cuckoo were able to ‘live’ peacefully with the Crested Goshawks but stayed at a distance to the left and right of the tree. We waited for an hour or so, while the elusive escapee Chinese Hwamei kept us entertained with it’s melodious song until a small size bird flew in. We looked among the branches and finally saw the Asian Emerald Cuckoo. And boy, are we excited! Though the bird was high up and mostly blocked by twigs and branches, camera shutters started to click non stop. The cuckoo was seen feeding on the caterpillars, hopped around a little but eventually stay perched for some time.
Javan Mynas and Black-naped Orioles were also observed flying to this tree on and off. The orioles does not seem to be afraid of the goshawks often coming close to them.
The goshawks were not happy with the presence of the other birds on the tree. They would scoop down and chase the cuckoos and other birds away, especially the Large-hawk Cuckoos. Many of the birders left happy with a rare Singapore “tick”.
The second half of the morning was spent waiting for the cuckoos to come back now that the goshawks were away. The Large Hawk-Cuckoo was the first to come back followed by the Indian Cuckoo. Only the Large Hawk-Cuckoo were seen feeding on the caterpillars.
An adult and a juvenile Large Hawk-Cuckoo were among the cuckoos that were enjoying the caterpillar feast at the Ficus Superba.
A group of birders were trying to find the Chinese Hwamei in the thick undergrowth when they spotted the Asian Emerald Cuckoo on a nearby tree. Shutters started clicking once again.
A most unexpected appearance of the Asian Emerald Cuckoo, last seen in 2006, was a most welcome X’mas present for both birders and photographers here.
The cuckoo stayed there for a few minutes before being distracted by a high pitch call, most probably by the Crested Goshawk. It then flew off to an higher tree branch. This ended my observation of cuckoos for the day. Sadly both the Chestnut-winged and Malaysian Hawk Cuckoos, that were seen yesterday, did not showed up this morning.
(All photos by Thio Hui Bing)
Reference: Yong Ding Lim Kim Chuah and Lee Tiah Khee. A Naturalist’s Guide to the Birds of Singapore. John Beaufoy Publishing.