Archive for February, 2006

Of termites and toads

Reading Subaraj’s posting on Termite Hatch reminds me that only about a week ago I was trying to explain the same phenomenon to my three year old daughter when we were at the carpark opposite Downtown East at sunset. A flock of House Crows (Corvus splendens) and Javan Mynas (Acridotheres javanicus) was feasting on a termite hatch. A couple of bats also arrived when it got a little bit darker.

Managed to catch one of the 2 cm long termites to show my daughter as it flew past. When I showed it to her, the two pairs of long wings simply dropped off. All my daughter could manage was. “…what happen to the wings? Gone already!”

The sight of those termites sends shivers down my spine. Why? In 1992 I was posted to an old camp in Seletar. We were doing guard duty that night after a heavy downpour and the termites decided to have a nuptial flight.

Initially it was bearable. A few of them were simply fluttering about around the lights. But later, we got a taste of what the Egyptians might have endured in biblical times. The lights were almost blocked out by the hoards, we had to turn off the standing fan because the metal cage around it was almost stuck full of the termites and it was splattering chewed up termites at us. Looked as if someone took a bottle of mayonnaise and decided to decorate the floor around it.

Many of them quickly lost their wings and were all over us and everywhere else. It was actually raining termites. Then the toads appeared in numbers that I have never seen in my life. Almost one toad per square meter at the peak. They were all over the car park and they didn’t even have to try catching the termites. They would have been stuffed if they just fed on those termites that were crawling on their bodies.

By about 10 pm, the activity died down. Most of the termites found a quiet spot to congregate. A few toads were still having supper. But we still had to contend with termites getting into our clothes when we went to sleep.

The next morning, when the guards were sweeping up the floor, the heaps of wings that piled up were really a sight to behold. Normally it is the tiny leaflets of the rain tree (Samanea saman) that form the heaps. But not that day! We may not have cherry blossoms (Prunus sp.) here in Singapore, but when the wind blew, the swirling detached wings had a similar effect.

Up till today, whenever I see a termite swarm, it still sends the shivers down my spine and I think of those frantic 2 cm long termites running beneath our army uniforms.

Contributed by Jeremy Lee, image by YC.

Mistletoes 4: Observations of a sometime bird watcher

Nearly every evening in early January, from about 6.00 pm, a pair of male Olive-backed Sunbirds (Nectarinia jugularis) (top) would settle down on my neighbour’s bougainvillea bush and spend some free time preening. In between preening they would simply sit tight, stretch their wings and enjoy the scenery. At exactly 7 pm when it was still light, they would suddenly fly off, where to, I do not know. Some days there would only be one bird.

On other days there would also be a pair of lovey-dovey Oriental White-eye (Zosterops palpebrosus) (bottom). I presume this was a pair, as the two birds would often sit close together, sometimes indulging in allopreening.

The Crimson Sunbird (Aethopyga siparaja) sometimes visit the bush but stayed only for a short while, never resting on a branch for more then a few seconds. They are the ones regularly visiting my noni tree (Morinda citrifolia).

These birds, together with Scarlet-backed Flowerpecker (Dicaeum cruentatum) and Brown-throated Sunbird (Anthreptes malacensis) were always around the mistletoe Macrosolen cochinchinensis when this plant was flowering and fruiting. This semi-parasitic plant grows on the branches of a nearby mempat tree (Cratoxylum formosum) that, thankfully have been left alone and not pruned away by the maintenance crew of the National Parks Board. When the mistletoe plants were flowering and fruiting, these birds enjoyed the copious nectar secreted by the flowers and the succulent berry-like fruits.

Being a regular perching bush of these birds that feed on the mistletoes, the bougainvillea obviously shows signs of the presence of their germinating seeds. These can clearly be seen growing on the stems of the bush (see germinating seed, above), no doubt in time to come, will weaken the flowering bush unless they are removed.

PS: About a month after the above piece was written, my neighbour’s bougainvillea bush was heavily trimmed by her gardener. The mempat tree was similarly pruned and most of the mistletoe plants removed, but not completely. I await the return of the birds when the plants grow back to their former glory.

Caterpillars and birds

Caterpillars are regularly eaten by birds. However, most birds avoid the noxious ones, especially those that are brightly coloured and hairy. Cuckoos (Cuculidae) specialise on caterpillars as these are their favourite food and they have no hesitation eating even the noxious ones. The arboreal species generally perch motionless on a branch looking for caterpillars. When a one is spotted, the bird grabs it and returns to its perch to eat it. Because caterpillar guts may be filled with indigestible and toxic leaf matters, the bird carefully removes the contents. This is done by biting off one end and gently thrash it against a branch. Once the gut contents are removed, the bird swallows it whole. Sometimes the caterpillar is passed back and forth through the bill to remove the contents. Hairy caterpillars are similarly swiped against a branch, not to remove the hairs, but to empty it of its gut contents. The birds apparently eat the caterpillars together with the hairs, the latter forming a mat in the stomach. These hairs are regularly regurgitated as pellets.

We give below two personal accounts of how two different species of local birds handle large caterpillars.

Robert Teo reported seeing an Oriental Pied Hornbill (Anthracoceros albirostris) in Pulau Ubin that caught a caterpillar of the Atlas Moth (Attacus atlas). This moth is the largest in Southeast Asia and possibly in the world. It’s bluish green caterpillar has a series of dorsal and sub-dorsal spines. The hornbill had the caterpillar in its beak and was vigorously shaking it before finally swallowing it.

Tan Hang Chong tells of another incident: “As I was birding along Lorong Sesuai some years ago, I chanced upon a Crow-billed Drongo (Dicrurus annectans). The bird was perched on a tree at eye level and I had the opportunity to observe it for a long while. What caught my immediately attention was that it had one of the largest tan-coloured caterpillar I had ever seen in its beak! The caterpillar was easily 15 cm long and as thick as my finger.

“The drongo started to move the caterpillar along its beak (ala cartoon characters eating a cob of corn). I initially presumed that the drongo was trying to flatten the caterpillar, the better to swallow it later. Thereafter, the drongo turned the caterpillar around, held it on its end and proceeded to swallow it whole. It surely looked like a most uncomfortable feat as the drongo’s torso was not much longer than the caterpillar!”

Contributed by Robert Teo and Tan Hang Chong, additional input by YC; image of Atlas moth caterpillar by Angie Ng and of hornbill by YC.

Interspecific interaction of birds at Pasir Ris

The place: near the Pasir Ris MRT Station, Singapore. The time: around 8 am. The date: 22nd December 2005. I noticed this whole assemblage of different species of birds on the grass, some foraging, others just looking around. There were crows, mynas, egrets and rock pigeons. More were continually joining in, especially pigeons and crows. The egrets didn’t really seem to mind and almost seemed oblivious to the 30-40-strong gathering before them.

Could the spot be a designated meeting ground for birds? After all, birds sometimes do communicate and discuss eating places, like Singaporeans. Or could the spot, judging from the seemingly limited interspecies interactions, be just a good spot for forage or rest? If the latter, it is amazing that there is no or little competition or observable territorial behaviour among different bird species!

Text and image by Lim Junying.

Comment by our bird specialist, R. Subaraj: I am glad that you were observant enough to notice this. Most people, including many birdwatchers, would have simply ignored the gathering as it mainly involved common urban species.

Based on the photo and what you have written, I would think that the area is a good feeding site. The Cattle Egrets (Bubulcus ibis) normally hunt insects in fields and the mynas and crows are opportunists who would also catch and eat insects. The patch of grass may be rich in invertebrate life due to some unknown reasons (dampness, freshly cut grass, etc.). As for the pigeons, they may focus on seeds but could be eating invertebrates as well, being highly adaptable.

As for competition, if there is plenty about there should be no problem. However, it may be interesting to study if they are working as a team, in a birdwave of sorts. A birdwave is a gathering of insectivorous bird species that move together to stir up more insects. This is a common occurrence in forests, from the lowlands to the mountains. The more birds involved, the more insects are stirred up and the better chance of finding a buffet, such as a tree of caterpillars.

Does this behaviour occur on the ground and in more open country or urban settings? Should be fun finding out.

Keep at it and nature never fails to amaze!

Yellow-vented Bulbul does swallow some fruits but not others

In an earlier posting it was said that Yellow-vented Bulbul (Pycnonotus goiavier) does not swallow Alexandra palm (Archontophoenix alexandrae) fruits. It pecks on the outer pulp, leaving the fruit on the branch with patches exposing the seed.

With the MacArthur palm (Ptychosperma macarthurii) (above), I have noticed that this bird does swallow the fruits whole. Although I have not seen it regurgitating the seeds, I did find a few patches of faeces with seeds on my driveway. It is possible that the bulbul passed out the seeds?

However, I have been puzzled by the presence of many individual seeds of this palm, cleaned of pulp, scattered along my driveway (left). I do not grow this palm in my garden. These seeds must have been regurgitated by some birds. Can it be the Pink-necked green Pigeon (Treron vernans) that regularly perch on the overhanging ceram palm (Rhopaloblaste ceramica) fronds?

And why does the bulbul swallows fruits of the MacArthur palm but not those of the Alexandra palm? The answer lies in the size of the two seeds. Alexandra palm fruits are nearly round, 12×10 mm, with a single large round seed that is about 9×8 mm in dimension. The flesh is a thin layer of 2-3 mm thick. Although the fruit of the MacArthur palm is of similar size, the seed is very much smaller. It is 10 mm long but only 5 mm broad.

Obviously we have much to learn about the feeding habits of our common birds.

Transverse sections of fruits of MacArthur (left) and Alexandra (right) palms.

Seeds of MacArthur (left) and Alexandra (right) palms.

Scale in mm.
All images by YC.

Next Page »

Welcome to the BESGroup website


"You can know the name of a bird in all the languages of the world,
but when you're finished,
you'll know absolutely nothing whatever about the bird...
So let's look at the bird and see what it's doing - that's what counts.
I learned very early the difference between knowing the name of something and knowing something."

Nobel Laureate Richard P. Feynman (1918-1988)

Locations of visitors to this page