BESGroup report for 2005

The year 2005 is coming to a close and 2006 is looming over the horizon. Let us take a few moments to review what we have done since the formation of the Bird Ecology Study Group.

The Nature Society had its last AGM in May 2005. This was where the idea of a new group was conceived. The group's blog was created soon after, in July, and launched with a series of postings on the nesting of the Zebra Doves. On 27th September the Executive Committee of the Nature Society (Singapore) formally accepted BESGroup as a new activity group under its umbrella.

So what have we done so far?
1. We have had formal discussions with NUS and NParks on joint activities and formal collaboration.
2. We initiated a series of talks under the broad heading "Why do birds do what they do?" and kicked it off with a number of talks by Luan Keng, Subaraj and myself. In the coming year we hope to continue with more, to expose birders to all aspects of the avian fauna – time and speakers permitting. We hope to explore aspects of bird migration, diet, habitat selection, flight, mating systems, vocalisation, evolution, etc., and share with members whatever knowledge we can glean from the literature and the net.
3. We are planning field trips to emphasise the ecological aspects of birds, not just their ID. In this respect we will be looking into the inter-relationship of birds with plants and other animals.
4. We plan to aggressively publish articles on bird ecology in the print medium, not only in Nature News and Nature Watch, but also in scientific and other journals and magazines that are published overseas.
5. We plan to link up with overseas bird groups and contribute to their activities.
6. We have an active blog (http://besgroup.blogspot.com/). So far there are in excess of 50 postings on subjects as varied as nesting, mobbing, anting and alcoholism in birds. We now have a team of more than ten birders submitting their observations regularly. The readership is increasing exponentially, approaching 4,000 hits after a short period of only five months.
7. We have familiarised birders with the term “anting” and so far four people have reported seeing this phenomenon. We have also made birders aware that not all birds swallow seeds to pass them out at the other end - some regurgitate them after the pulp is removed in the gut. We plan to further seek out unfamiliar and seldom mentioned aspects of bird ecology and bring them out into the open for discussion.
8. We have an active yahoo discussion loop and will be starting a discussion board soon, thanks to Jacqueline Lau. We also hope to have our own web page in the near future.
9. And finally, we are proud to announce that the group is closely associated with the Singapore Hornbill Project that is currently going on in Pulau Ubin and the Jurong Bird Park (details later).

For 2006 we will be offering not only more of the same but other new projects and ideas. After all, BESGroup is a young group of enthusiastic people brimming with new and novel ideas and raring to go.

Have a great 2006. BESGroup plans to do just that!

YC Wee, R Hale, R Subaraj & G Pereira
30th December 2005

Folivores - birds that feed on leaves

Cheong Weng Chun sent me an image of a juvenile Asian Glossy Starling (Aplonis panayensis) with a bunch of young rain tree (Samanea saman) leaflets in its beak. And in his own words, the bird was: "chewing - no, can it chew or perhaps, I should say swallow?"

This started me asking a pertinent question "Do birds eat leave?" Well, some birds do... Anyway, I ended up with some interesting information.

Folivory applies to those birds that eat leaves, either exclusively or partially. Although a successful foraging strategy for numerous species, few birds are exclusively folivorous. Why? Because flight demands an enormous amount of energy and leaves do not provide the necessary energy. The energy content of leaves is only half that of fruits and a quarter that of insects and other arthropods. Also, leaf digestion is slow and requires a large storage space in the gut. Besides, digestion needs to be undertaken by specialized bacteria present in the gut

Those birds that regularly feed on leaves have thus turned to gliding or abandoned flight altogether.

Only about 3% of all birds, from at least 14 families, eat leaves regularly. Most of these birds are terrestrial or aquatic and only 5 families include aboreal members. From these 5 families only 2 species, Hoatzin (Opisthocomus hoazin) and Owl Parrot (Strigops habroptilus) obtain most of their energy from leaves. These include new growth of green leaves, buds, flowers and fruits in season, moss and fungi. Hoatzin is a South American bird whose flight is weak and awkward. It clumsily creeps up branches and make only short flights. The other is a flightless bird of New Zealand.

R. Subaraj notes that certain birds offer leaves during courtship, but we have an immature bird here. So does it mean that its behaviour is precocious?

Image by Cheong Weng Chun

Angie's nesting crows - 1. A nest in the making

A pair of House Crows (Corvus splendens) started building a nest on 19th December 2005 in an angsana tree (Pterocarpus indicus) just outside my apartment window. The day before they were building another nest on the far side of the tree. Unfortunately it disappeared overnight, probably foiled by strong wind during the night. They appeared to have succeeded now, as they were still building it on the second day. I hope the nest remains.

Even as the nest was just only a dozen or so twigs propped across the forked branches, a female Asian Koel (Eudynamys scolopacea) had made a quick inspection when the crows were away.

Both crows were equally involved in collecting and arranging the twigs for the nest. With sunbirds and flowerpeckers, the males merely accompany their mates and just hang around, never helping in wool collecting.

Yesterday, the nest looked like an untidy collection of dry twigs, with a few green leaves added. Today it looks more compact and increasingly I have difficulty seeing what they were doing when both happened to be behind that nest. This morning they were still compacting the nest with more twigs. Sometimes they arrived without any twigs but took turns or even together shifting twigs around the nest. Will they be bringing 'fibrous' materials tomorrow to line the inner cup?

I wonder where they got their materials from? They don’t seem to just pick up the fallen twigs from under the tree.

These crows appear to be loving birds, always standing close, 'kissing' each other and one was seen feeding the other, although I could not see what was passed from one beak into the other’s throat.

The image of nest was taken at 4.45 pm today.

Contributed by Angie Ng, 21st December 2005

Anting III

Now that anting has been unleashed onto the birding community, more episodes are being reported. This posting gives the third and fourth accounts after Kelvin’s historic observation 17 years ago, followed by Jeremy's.

R. Subaraj, our bird specialist and nature consultant, relates his experience: "When I was at the National University of Singapore campus in Kent Ridge on November 25th, 2005, I noticed a solitary Javan Myna (Acridotheres javanicus) approaching me not far from the Science Canteen. As it walked toward me, it picked up something from the ground and put it under its wing. I kept observing it carefully and the next time it did the same thing. I suddenly realised that it was a kerengga ant (Oecophylla samargdina) that it was stuffing under the wing.

"Immediately remembering what Kelvin had seen not far from where I was 17 years ago, I continued observing it. The bird was deliberately searching for more krenggas in the grass, along the drain and even in the drain. Each one it caught was quickly stuffed under the wing as well, occasionally with a little dance to follow.

"Another myna, another anting session!"

Margie Hall relates her story: "I recently found my 1989 notebook and can give you two more brief accounts of anting: March 9th, 1989, 2 pm, White-vented Myna picking up red kerengga ants one by one (7 in all) and putting them in underparts and in wing feathers. May 9th, 1989 White-vented Mynas 'anting' with red kerengga ants. Note: White-vented Myna probably means Javan Myna - I think I was using the names interchangeably in those days."

Feeding protocol among some common birds

K.F. Yap’s notes that there seems to be a kind of unwritten ‘pecking order’ among the common birds around us when they feed, see also The ubiquitous Javan Myna. Whenever cleaners remove refuse, Javan Mymas (Acridotheres javanicus) , being most bold and aggressive, would be the first to feed, even when people are around. House Crows (Corvus splendens), although they are larger and more aggressive, usually stay back as they are shy of people. The crows would come to feed after the cleaners have moved away, during which time the mynas would also have moved on.

He also observed that whenever his neighbours threw stale bread and rice out of the backyard windows to feed the birds, the pigeons would come first, then the mynas and finally the crows. The crows would then rob the pigeons and mynas of their food, he concluded.

Intrigued by his account, I hung out a bunch of ripe bananas on a low branch in my garden. Interestingly, Yellow-vented Bulbuls (Pycnonotus goiavier) were the first to arrive. They would perch on the bunch and feed on the ripe bananas. Only when the bananas fell to the ground would the Javan Mynas congregating below move in to feed. There would be tussles between rival pairs of mynas fighting to be the first to feed. Invariably every bird had an opportunity to feed. This is because of their method of feeding – making a quick move towards the fruits and taking a chunk to move away to feed. This allows others to move in.

I am surprised that the bulbuls were left in peace up on the banana bunch as on the ground, the mynas would always chase them away. Is this niche feeding? Are mynas ground feeders? Do they find it difficult to feed perching on the bunch?

According to R. Subaraj, mynas are primarily ground feeders though they will feed on fruits in trees where they can perch comfortably adjacent to the fruit itself.

Anting II

I have kept several mynas in my lifetime. One of these was a male Common Myna (Acridotheres tristis) that I rescued from the cat as it landed on the ground during his maiden flight. This bird accompanied me almost everyday afternoons and evenings when I patrolled the condo looking for some animal or insect to observe.

At a very young age (it was still begging for food), the bird enjoyed a good bath, splashing water with its wings. That was when I placed him in the sink together with the ice cream box in which it was kept, and slowly ran the tap, intending to wash the tub and at the same time give the bird his first bath. But before I could do anything, he instinctively reacted to the water flowing beneath his feet. He dunked his chest in the water and splattered water all over the toilet. So much for bathing 101, this candidate was earmarked for direct PhD in bathing. Eventually I even placed him in a tub of water that was so deep that only his head was above the water level. The lure of a good bath never stopped him. But he was very cautious with water levels more than 3 inches deep.

We used to patrol the greenery around the condo together for his evening snacks. Anything I chased out from the grass, he would grab and eat it. Whenever there were other mynas around he would start a fight. With my help he would invariably win. One evening, he happened to walk over an ant mound. Initially intrigued by the ants, he later found them to be foul tasting and started to attack them. The ants responded by mobbing him and crawling all over his feathers. I had seen many young birds killed by ants and was a little concerned by the increasing number of ants crawling onto him. But as much as I tried to discourage him from mucking around with the ants, he kept at it, to stupidly stand right on top of the mound. His behaviour took me by surprise. Intermittent between his initial actions of attacking the ants, he suddenly prostrated himself on the ground, spread his wings and puffed up his plumage. I had thought that he had a few ant bites too many and was getting injured. But he appeared absolutely fine. So I stood by and observed for a while. After about two minutes of intense 'anting' he suddenly moved away from the ant mound and preened itself to get rid of the ants. All of a sudden his intense interest with the ant mound vanished and we were back looking for tasty afternoon snacks.

After that he would regular 'ant' itself once a week or less, probably because I gave him a daily bath.

The fact that this bird had never observed another 'anting' but seemed to know what to do with ants points in the fact that this behaviour seems to be innate, although wild birds seem to do it more professionally. My little 'Sidewinder', as I called him, apparently had some ideas of what 'anting' was all about, hard coded in his brain.

Contributed by Jeremy Lee

Javan Myna hunted by an Accipitrid

Because of the outbreaks of avian flu around the region, everyone is nervous when encountering a dead bird. Thus when John Lynn’s daughter saw a dead bird in her garden, she was naturally nervous and called her father at work.

Lying in what John described as his “bird friendly” garden was the carcass of a bird with its feathers scattered around. Its guts were missing. It must have been quite a sight to witness a bird butchered thus. The father pacified the daughter explaining that it must have been a “hawk kill” and not to worry about it.

A few moments later she again phoned John, this time in panic. Apparently the hunter had returned to finish off its prey. Sensing the unfolding of an exciting drama, he again pacified her and told her to get hold of the camera and record the event. This she did. The bird was very protective of its prey, spreading out its wings in anger when she got too near. It took an entire hour for the bird to finish off its prey, leaving nothing except feathers.

Although the jury is still out, the general agreement is that the bird is an accipitrid, either a juvenile Japanese Sparrowhawk (Accipiter gularis) or a Besra (A. virgatus), the latter being a rare migrant to Singapore.

These birds usually hunt small passerines, relying on the element of surprise to catch their preys. The bird may wait, hidden in a tree, to suddenly dart forth at a passing bird. It kills its prey mostly using its feet and talons.

Text and image by John Lynn;
R. Subaraj and Morten Strange provided expert opinion.

Mobbing of predator birds

Many species of birds exhibit ‘mobbing’ tendencies, especially when they find predator birds resting alone or in small groups. Even those that are predominantly scavengers or fish-eaters are similarly mobbed. Such harassing behaviour is aimed at driving the predators off and in most cases they succeed. Mobbing is more pronounced if there is nesting involved, especially if eggs or young are present.

It is a common sight around Singapore to watch House Crows (Corvus splendens) flying after and driving off resident and migratory raptors of any species. I have personally seen Black-shouldered Kite (Elanus caeruleus), Brahminy Kite (Haliastur indus), White-bellied Fish-Eagle (Haliaeetus leucogaster), Oriental Honey-Buzzard (Pernis ptilorhyncus), Changeable Hawk-eagle (Spizaetus cirrhatus) and many other species being mobbed. House Crows do this individually or in a group, within and above their territories. Dr Wu Eu Heng has also reported seeing House Crows mobbing a Changeable Hawk-eagle around Jurong. Other bird species such as Black-naped Oriole (Oriolus chinensis) and Dollarbird (Eurystomus orientalis) also mob raptors in flight.

At many nature areas, particularly wooded areas, you often come across a party of highly agitated birds noisily moving around a tree or bush. Usually, this indicates the presence of a predator. In most cases this would either be an owl or a snake and the birds will both mob and scold in an aggressive manner. Greater Racket-tailed Drongo (Dicrurus paradisus) and Striped Tit-babblers (Macronus gularis) are often involved in such behaviour in the local forests.

Mobbing birds may comprise one or more species. It is a great opportunity to not only observe the irritated flock but to discover an usually illusive predator. I have seen some great snakes and owls in this manner. For example, the first Barred Eagle Owl (Bubo sumatranus) that I encountered in Malaysia was one that was being mobbed by a few bird species, including the Asian Fairy-Bluebird (Irena puella).

I am sure many birders would have encountered instances of mobbing and we would love to read about some of their accounts.

Contributed by R. Subaraj
Additional input by Dr Wu Eu Heng.

More on Javan Mynas

The Javan Myna (Acridotheres javanicus) is a rather interesting bird despite it being an exotic species. But we must all agree that there is still a lot that we do not know of this bird, however frequent it is sighted. See also earlier post.

Back down the years, my father saw gangs of these mynas fighting. Each group comprised of up to 20 individuals. The fight was even more peculiar. Two birds would clasp their claws together and engaged in a frenzy of beating wing and wild pecking. My father had personally seen them so engrossed with their fight that a passing van made roadkill of them.

"Gang fights" were often to the death. These were one-on-one battles where each member of a gang took on another from the other gang, instead of a wild 4-5 mobbing a single bird. And only one myna of the fighting pair walked away alive.

I myself have seen milder versions of such fights. It involved small leaps, accompanied by flapping of wings to prolong time in the air, and a brandishing of claws. This was usually enough to send a weaker opponent away. I have seen this in foraging mynas. One individual, probably a misfit, was constantly chased away by one individual of a group. Usually, the myna that was chased away picked another foraging spot.

From all this, it is easy to conclude that they have very complex social behaviour. And if so, how do they find mates? I have read that a myna mates for life, one reason why most of them forage in pairs. But if so, would a gang have an even number of individuals, made up of many of such pairs? Or would it comprise separate individuals with no sexual relationship to the others?

Territorial behaviour of mynas is of course more than just fights, there could be some kind of warning first. I often see the birds performing a kind of head movement. The myna would ruffle up its feathers (probably to make itself look bigger to opponents), and start bobbing its head up and down, which is sometimes accompanied by a shrill or a single call that is repeated. I have no idea if this is territorial behaviour, because I have also observed mynas that became violent without prior warning. Worse still, whenever I spot a myna performing the "head-bob", I rarely see any other mynas around.

I also start to wonder whether only the male does it. I observed one of a myna pair near the edge of the road performing the "head-bob". After it was done, the other myna beside it started to do the same. If it was a pair of one male and one female (life mates), then I can be sure that both sexes perform it and territory (if it was territorial in the first place) was "held on" by both members of the pair.

Can anyone shed some light to the above?

Contributed by Lim Jun Ying, a young birder with an inquiring mind

Comments by our bird specialist, R. Subaraj: Gang fights by Javan Mynas can indeed be pretty vicious and they are oblivious to nearly everything around when they are engaged in battle. Fights are often between separate packs, two pairs or sometimes, they seem to attack one particular individual. After it is over, it is not uncommon to find feathers everywhere and sometimes a wing as well. As for the headbobbing and ruffling of head feathers, here is a subject for study to determine the actual reasons behind it. It certainly looks like irritation and I have observed mynas ruffling their head feathers and muttering in their own language at me!

The ubiquitous Javan Myna

The Javan Myna (Acridotheres javanicus), formerly known as White-vented Myna, was brought into Singapore around 1920. Since then it has become very successful, especially in urban areas. The aggressive nature of this introduced myna has successfully displaced the once common Common Myna (A. tristis). Margie Hall laments the fact that back in the 1990s she used to see a group of up to ten Common Mynas by the beach at Sembawang Park, but for the last five or six years she only saw a couple or couple and immatures. And around Singapore she wonders whether anyone has ever seen more than a couple.

Indeed, the Javan Myna is extremely adaptable in terms of food and breeding sites. Our bird specialist, R. Subaraj, reports that it wakes up well before other birds to feast on road kills along our expressways. S.K. Kwan mentions that some 11 years ago she saw a myna making its nest slotted between the wall and the building signage at Magazine Road. They usually nest in the eves of house, as Margie rightly points out. She further adds: "They are seen going in and out the holes between beams in the above ground MRT line at Sembawang."

My experience with this myna is in my garden. Whenever I do weeding, turn the compost or repot root-bound plants, there will always be at least one pair following me. Apparently these birds take the opportunity to catch insects and other invertebrates my activities invariably uncover. I am not the only person to notice this as Margie has similar experience in her garden. She further notes that the birds are always present whenever grass cutters are around.

These birds remind me of the Cattle Egrets (Bubulcus ibis) that were always around cattle that once roamed freely along our roads. But such a scene is no more, ever since the government long ago issued a veiled threat to round up the cattle, slaughter them and distribute the meat to charity homes.

Javan Mynas are scavengers and never miss an opportunity for a free meal. K.F. Yap reports his observations around Housing and Development Board’s apartment blocks. When cleaners empty the garbage bins each morning, huge flocks gather around. There will always be House Crows (Corvus splendens) too, but these shy birds will station themselves at a safe distance away. Only after the bins have been replaced and the bin-doors closed, and well after the cleaners have gone to the next garbage chute and the mynas have left the scene, will these crows fly in to forage.

Margie Hall adds her observations: “There is (or was for several years until recently, but then I have not made the turning at the same time as a garbage truck in the last few months) a group of five or six Javan Mynas who hang around Yishun Avenue 1 near the junction with Sembawang Road, where there is an extra right hand lane for traffic to wait for the right hand turn. Garbage trucks en route to Senoko regularly drive along Yishun Avenue 1, stopping at the junction in order to wait for the right hand turn. The mynas fly onto the back of the garbage trucks to see what they can find. As the trucks move forward to make the turn, the mynas stay on them. Only when the trucks have done the complete right hand turn and are accelerating on Sembawang Road do the mynas fly off the trucks and fly back to the trees near the waiting lane, to wait for the next truck!”

Jeffrey Low recalls seeing mynas doing something similar to fruit and vegetable trucks along the North-South Highway in Malaysia. They hop on and rummage through the fruits and vegetables until the trucks (presumably) rolls out of their territory or comfort zone before they hop off.


Contributors: K.F. Yap, Margie Hall, Jeffrey Low, S.K. Kwan and R. Subaraj.

I and the Bird #12: The Canterbirdy Tales

The #12 'I and the Bird' carnival has The Canterbirdy Tales as its theme. The host this time is David Ringer and BESGroup's contribution is the article on Pink-necked Green Pigeons 3 - Sharing of duties. Click on the link and have an interesting read.

Pink-necked Green Pigeons 3 – Sharing of duties

In Pink-necked Green Pigeons both parent birds help in egg incubation and care of the nestlings. The male takes on the day shift, arriving at the nest at around 8 am. He stays in the nest all day, never leaving unless disturbed. The female arrives at around 5 pm and stays in the nest the entire night. Arrivals and departures may be delayed by up to 1.5 hours, especially when the birds detect people around. Like nosy photographers or birdwatchers hidden behind a screen some distance away.

Shift change is the most exciting moment. Usually the bird in the nest becomes slightly excited and moves around a bit when its partner is nearby. Sometimes there is soft gurgling vocalisation from either party. Then suddenly a bird flies in with a distinct flapping of wings to join the other in the nest. The latter moves slightly away to allow the former to sit in the nest before flying off. At times when people are around, the bird may fly in to land on a nearby branch, to move slowly towards the nest as the other bird flies off. Or the bird in the nest may suddenly fly off, the other flying in a few seconds later.

During egg incubation the bird sits quietly in the nest all the time. After the eggs are hatched the parent birds similarly sit quietly but the nestlings are always moving about. Most times the latter would pester the parent in the nest for food. This they do by pecking the parent around the neck area. The parent responds by opening its beak to allow the nestling to poke its beak in to receive the liquid crop milk. During this transfer of food, both necks may twist around somewhat until the transfer is complete. Food transfer occurs at intervals and may again be seen just before the bird leaves the nest. If not, the arriving bird will have to feed the nestlings.

Such a method of feeding allows for the parent birds to remain in the nest all the time, thus providing 24 hours protection to the nestlings. This is sharply contrasted to those birds that need to seek out fruits and insects to feed the nestlings. The nestlings of the Yellow-vented Bulbuls (Pycnonotus goiavier) are left alone for varying periods of time when the parents are away foraging.

Image shows the male just after arriving and the female just before departing, together with one nestling.

Richard's "Owler" - The mobbing of a Spotted Wood-owl

Years ago when I was living at a house in Swiss Club Road whose garden abutted the then Turf Club's outer car park, there was a pair of Spotted Wood-owls (Strix seloputo) living in some old trees just inside and outside the garden. They were resident for several years until their favorite tree blew down in a storm one day and they apparently moved away. Virtually any morning, if it had rained in the night, I could go down through the gate and find the pair drinking and bathing in a particular puddle. They took little notice of me as long as I remained at a distance. Would that I had been as interested then in photography as I am now, but I wasn't, and so have no pictorial record of this.

On one occasion I heard a lot of noise at the bottom of the garden in mid afternoon and walked down to see what was going on. There on a branch about twenty feet up sat two adult Spotted Wood-owls and two young ones. Some yards away on other branches were four Oriental Magpie-robins (Copsychus saularis) vociferously telling the owls to go away. The owls were taking not the slightest notice of this and ignored me. In due course the Oriental Magpie-robins gave up and peace reigned once more.

Contributed by Richard Hale


Comment by R. Subaraj: Great account! So little is understood about the Spotted Wood-owl that even their bathing in a puddle provides good data. Then you have the breeding record of this uncommon owl. I do not recall any other breeding records from the Swiss Club Road pair. Finally, local confirmation that the Oriental Magpie-Robin, also dislikes and protests the presence of a potential predator within it's territory... from a distance of course.