Juvenile birds begging for food

Nestlings are continuously fed by the parent birds as they are unable to fend for themselves. They can be seen bills agape, excitedly making soft calls whenever their parents arrive. These nestlings start to beg for food whenever their parents are around, either hearing the latter’s calls or actually seeing the parent birds around the nest. Vibrations as a result of the parent birds landing nearby will also trigger begging. In cavity nesting birds, the darkening of the nest as the parent bird enters the cavity triggers begging. Among some swifts air currents as a result of the adults’ arrival will do the trick.

Among recently fledged birds, the parents continue to feed them for some time before the former are independent enough to forage for themselves. During this period, the juveniles will persistently and noisily beg for food. At the same time they will crouch open-billed and flutter their wings while begging. This behaviour is said provide visual and acoustic cues to the parent birds that stimulate feeding.

Such begging posture and begging call are more or less the same in most species of birds. This has led to the adult birds sometimes feeding the wrong species, be it birds or other animals. In fact there is a picture of a Northern Cardinal feeding goldfish for a few days at the edge of a garden pond (p. 8.107, Winkler, 2004). The bird was seen stuffing mouthfuls of worms into the gaping mouths of the goldfish, obviously mistaking the gaping mouths for those of its nestlings.Reference
Winkler, D.W. (2004). Nests, eggs, and young: Breeding biology of birds. In: Podulka, S., Rohrbaugh, R.W. Jr & Bonney, R. (eds.) Handbook of bird biology. Ithaca, New York: Cornell Lab of Ornithology, p 8.1-152.

Credit for images from top: Yellow-vented Bulbul (Pycnonotus goiavier) nestling (YC), Pacific Swallow (Hirundo tahitica) fledgling (Chan Yoke Meng), Oriental Magpie-robin (Copsychus saularis) fledgling and parent (YC) and Asian Koel (Eudynamys scolopacea ) fledgling (YC).

Black Bittern the hunter

As mentioned in the previous post, the Black Bittern (Ixobrychus flavicollis) is a rather uncommon winter visitor to Singapore. It foraged around an artificial lake in Jurong in November 2006, appearing extremely tame and allowing groups of birders and photographers to view and to record. The bird exhibited its skill in fishing with a sudden extension of its retracted long neck. The next moment it had a sea-bass fingerling (Lates calcarifer) firmly impaled in its upper mandible (above). In the image below the bird had caught a tilapia fry (Oreochromis mossambicus). Once the bird successfully caught a fish, it quickly retreated under cover of the vegetation to enjoy its meal. In the case of a biggish fish, it adjusted it so that the head was swallowed first. This is to ensure that the spines of the fins would not damage the throat. Within a minute or two the fish was completely swallowed (below). As with herons, the fish enters the gizzard where the flesh is stripped and passed on through the stomach while the bones and scales are compressed and finally ejected as a pellet.

Input and images by Meng and Melinda Chan, fish identification by Dr Khoo Hong Woo.

Black-naped Oriole manipulating a cocoon

In October 2006 Meng and Melinda Chan chanced upon a Black-naped Oriole (Oriolus chinensis) snatching a whitish cocoon from the branch of a tree (above). The thick, tough silken covering that made up the cocoon was a challenge to the bird (below). Gripping the cocoon in its bill, the bird furiously rubbed it against a branch in an effort to remove the silk covering (below). In less than three minutes it succeeded in removing most of the cocoon silk to get at the succulent pupa inside (bleow). In a flash it swallowed the defenceless pupa. Satisfied with its meal, the bird gave a short call (below). Many moths and a few butterflies weave a cocoon of silk, inside which the caterpillar pupates. These cocoons are thick and tough or they can consist of a few strands of silk that keep the pupa from falling, or hold materials together to form a shelter.

Cocoons may be formed from substrate materials held together by silk. Some are so tough that they need a special escape lid woven to the end for the emergence of the adult, like the silkworm. The cocoon of the Atlas Moth (Attacus atlas) (above) is a good example of how tough the silken cover is. The image below shows the longi-section of the cocoon with the remains of the pupa after the moth had emerged.
Khew Sin Khoon, who operates the website Butterflies of Singapore (http://www.geocities.com/RainForest/Vines/2382/index.html), agrees that the cocoon is most probably that of a lepidoptera. He believes that it is probably that of a moth rather than that of a butterfly. Why? Because there is too much silk and “the fuzzy stuff” to be that of a butterfly.

Input by Melinda Chan, images of oriole by Chan Yoke Meng and those of the Atlas Moth cocoon by YC.

Laughing Kookaburra

The kookaburras are the largest members of the kingfisher family and they are heard as much as they are seen. The Laughing Kookaburra (Dacelo novaeguineae) is well known for its loud crackling laugh, usually heard at dawn and dusk. At other times during the day, sudden outbursts may occur when the bird succeeds in capturing a prey.

The bird that Gloria Seow saw in the Blue Mountains in New South Wales, Australia in September 2005 did just that. Despite having a field mouse clamped tightly between the mandibles, the bird was making its infamous laugh.
The bird usually perches for long periods on a branch or tree stump keeping both eyes open for any possible prey. Once it spots one, it pounces on it to take it in its bill. Small items are swallowed whole while large prey are beaten against the ground or taken back to the perch where it is first bashed against a branch before swallowing. It takes frogs, lizards, snakes, insects, snails and even small birds and their eggs.

Generally these birds are tame and allow one to come quite near. Thus Gloria was able to come pretty close to take the picture above using a x6 zoom camera.

The bird was perching on an eucalyptus tree (Eucalyptus sp.), also known as a gum tree. Thus Gloria actually saw the kookaburra “sitting on an old gum tree” alright. And heard it laughing.

Input and image by Gloria Seow.

Tiger Shrike: Postscript

Gloria Seow was holidaying in Japan in October 2006 where she scored 77 lifers even though it was off-season for birds then. But that would be another story. What she e-mailed me was an interesting image of a dried-out field mouse. It was impaled upon a low bush growing in an open grassland bordering a marshy area in Hokkaido (below). According to the Japanese birders who accompanied her, it was possibly the work of a Bull-headed Shrike (Lanius bucephalus).
We have three species of shrikes. Tiger (Lanius tigrinus) and Brown (Lanius cristatus) are winter visitors as well as passage migrants while Long-tailed Shrike (Lanius schach) is a common resident. But according to our bird specialist R. Subaraj, "Long-tailed Shrikes are actually very uncommon residents with some movements that are not fully understood. That is why they tend to be at known sites at only certain times of the year. Additionally, there is sometimes an influx of this species.....migrants?"

Shrikes have the reputation of impaling their preys on sharp thorns. They are thus known as “butcher birds. We have an earlier posting on a Tiger Shrike dismembering a large scarab beetle and another on the bird swallowing a lizard.
R. Subaraj reported seeing the headless corpse of a Yellow-rumped Flycatcher (Ficedula zanthopygia), impaled on a thorn of a short tree that he suspected was the work of a Long-tailed Shrike. And in Malaysia he once came across the "larder" of a wintering Brown Shrike consisting of impaled insects along a stretch of barb wire.

What we did not have is an image of a vertebrate impaled by a shrike. Now we have, thanks to Gloria, although it is not local but from Hokkaido.

Now here is a challenge to birder-photographers. Look out for a shrike-impaled prey and bring back an image!

Input and images by Gloria Seow.

Yellow-vented Bulbul: Food for the nestlings

The Yellow-vented Bulbul (Pycnonotus goiavier) is one of the more successful urban birds in Singapore. Part of this success is its ability to adapt to its food source. It is omnivorous, that is, it will eat insects as well as a range of fruits. At the same time it also scavenge on scraps of discarded food. Newly hatched nestlings are fed with insects and other invertebrates. The growing nestlings require a constant supply of protein. This keeps the parents busy bringing such food constantly.

Almost every garden in Singapore will have at least a pair of Yellow-vented Bulbuls. On certain months of the year the loud and somewhat pleasant bubbling songs in the early morning and later evening are music to the ear.

These birds are so used to humans that they will build their nests among ornamental plants grown in gardens or in potted plants placed in balconies or even along the verandahs of high-rise apartment buildings. The nests are deep cups made from grass, dry leaves, etc. Looking untidy from the outside, it is neatly lined inside.


Lena Chow recently sent an image of a pair nesting among her artificial plants (below). Talk about getting used to urban living…

Images of bulbul by Tang Hung Bun; nesting among artificial plant by Lena Chow; input by YC.

Ruddy Kingfisher and pellet casting: Postscript

The earlier post on the Ruddy Kingfisher (Halcyon coromanda) coughing out a pellet about an hour after it ate a snail noted that the photographer missed getting an image of the pellet coming out of the bird (above, top). Well, Meng pointed out that I should examine closely the throat of the bird in the first two images. I did as suggested and also adjusted the contrast of the images, and there in the throat is a dark object - the pellet (above, bottom; below). The first two images of the earlier posting showing the initial stages of the coughing thus clearly show the dark pellet about to be ejected. The third image where the bird is crouched low shows a clear throat, indicating that the pellet has already been coughed out (below).
Most kingfisher pellets are white, reflecting on the food they eat - fish. The composition of these pellets are mainly fish bones. These bones are collected in the gizzard and compacted into pellets to be subsequently coughed out. Should these bones be allowed to pass on to the stomach, imagine the damage they could cause to the bird.

In the above case the pellet is black as the bird earlier ate a snail. Obvioulsy it did not completely remove all the shell fragments.

Thanks to Chan Yoke Meng for the use of the images. It is his keen eyes that spotted the pellet in the throat of the bird in his images.

Ruddy Kingfisher: Eating a snail, then casting a pellet

The Ruddy Kingfisher (Halcyon coromanda), an uncommon passage migrant and winter visitor to Singapore, made a brief appearance of a few days towards the end of October 2006. Once news got around, birders and photographers congregated at Jurong, near the Chinese Garden, to get a glimpse and/or to take a picture of this rare bird.
Allan Teo was among the fortunate few who witnessed the bird manipulating a snail. After it got a firm hold of the mollusc in its bill, it expertly removed the shell by smashing it against the perch, first against one side, then against the other (above). It then used the horizontal force of its head swing that resulted in the smashed shell pieces flying apart, leaving only the meat. Happy with the shell-less snail, the kingfisher swallowed its prize catch (above: note damp patches on either side of the bird's perch where the snail was whacked).

After having their fill with the kingfisher, most of the people moved off to look for other rare birds. The few who patiently remained witnessed an usual event, the casting of a pellet. This came more than an hour after the kingfisher consumed the snail. The bird first made some sort of retching action, giving the appearance as if it was about to vomit. Then the bill widened substantially to show the large gape and equally large opening into the throat (above). At the same time the body bent forward - and suddenly out popped the pellet (above). Unfortunately the actual moment when the pellet appeared was not caught on film.

The pellet ended in the undergrowth below the tree and it would be like looking for a needle in a haystack to try retrieve it.

Input from Allan Teo, images by Allan (top three) and Chan Yoke Meng (bottom three).

Feeding habits of kingfishers

A kingfishers generally hunts by sitting quietly on a high perch and keeping a close lookout of the surrounding for potential prey. Once it spots a prey, it swoops down and seizes it in its bill to return to the same perch or another perch. Alternatively, the bird may snatch a prey while in flight or hover in front of a branch to catch the caterpillar of the privet hawk moth. Now not all kingfishers eat fish. Certainly fish is the food of many kingfishers but most of these birds eat a wide range of foods. These may include invertebrates like worms, centipedes (above), insects (below), molluscs and crustaceans. They also eat vertebrates like amphibians, reptiles and mammals. Plants are seldom eaten but there are reports of the Common Kingfisher (Alcedo atthis) eating the stems of reeds. Belted Kingfisher (Megaceryle alcyon) has been known to eat berries occasionally while the Blue-breasted Kingfisher of Africa feeds on oil palm fruits (Elaeis guineensis).

The Stork-billed Kingfisher (Halcyon capensis), with its large bill in relation to it body size is well adapted to dealing with crabs. And large fish also. Daisy O’Neill wrote an account of how one such kingfisher dealt with a fish larger than its head, whacking it to death before swallowing it. Now Allan Teo has sent in images of another Stork-billed Kingfisher that caught a fish, gripped it tightly in its large bill and smashed it against its wooden perch. The bird then casually tossed the dead fish into the air to reposition it for swallowing head first. The image is so clear that the bruises on the fish’s head are clearly visible.

The beating, besides stunning or even killing the fish, also breaks up its spines that might otherwise cause harm to the bird when swallowing it. It is interesting to note that there have been cases of kingfishers dying as a result of these spines becoming lodged in the bird’s digestive tract.


Top two images of the Collared Kingfisher (Todiramphus chloris) are by Chan Yoke Meng; bottom two of the Stork-billed Kingfisher are by Allan Teo.

More on Tiger Shrike

An earlier posting on how a Tiger Shrike (Lanius tigrinus) meticulously dismember a scarab beetle lamented the fact that there has not been any report of the bird taking vertebrates in Singapore. It is very possible that someone may have seen the incident to subsequently forget about it. This is exactly the situation. After reading the blog, Mike Hooper kindly sent an image of a Tiger Shrike swallowing a lizard, seen at the Kallang Riverside Park on 7th October 2006 (above).

And according to our bird specialist R. Subaraj: “…not enough of the lizard remains visible for a positive identification but I suspect that it might be a young Changeable Lizard (Calotes versicolor), based on the long tail and the yellowish colouration of what is visible.

And Subaraj continued: “Several years ago, at Marina East, I came across the headless corpse of a Yellow-rumped Flycatcher (Ficedula zanthopygia), a migrant, impaled on a thorn of a short tree. Though there was no direct evidence, I suspect that it was the doing of the local Long-tailed Shrike (Lanius schach).

“In Malaysia, I once came across the "larder" of a wintering Brown Shrike (Lanius cristatus). It had impaled a selection of insects onto the barb wire on the top of a perimeter fence! Modern adaptation?” Coming back to the shrikes, according to Chan Yoke Meng, these birds have no problem feeding on caterpillars, spiders and other invertebrates. They usually swallow them within seconds (above: top Brown, lower Tiger). As with raptors, bee-eaters (a,b), herons and kingfishers, shrikes cast pellets of undigested parts of the food they eat. The image above shows the bird after casting the pellet while the lower image shows the pellet. Beetle parts are clearly seen.
Input by Mike Hooper, R. Subaraj and Chan Yoke Meng. Images by Mike (top) and Meng (the rest).

How the Tiger Shrike dismantled a beetle

Shrikes are songbirds. But when they hunt they behave like little raptors. An earlier posting showed how aggressive a juvenile Tiger Shrike (Lanius tigrinus) was when eyeing the white-eyes in a cage. Given a chance we are sure it would have devoured one of the caged birds. The diet of these shrikes consists of large insects and small vertebrates that include songbirds, reptiles, rodents and even mammals. So far there has not been any local report of a shrike capturing a vertebrate prey. But in mid-September 2006 we observed a juvenile Tiger Shrike manipulating a large scarab beetle (above).
The juvenile bird was on a perch, looking handsome and posing for the camera. But it was actually eyeing the surroundings. Suddenly it dived towards the ground and caught hold of a scarab beetle by one of its legs (above). Returning to its perch and with one of its feet holding down the beetle, it started to stab the wriggling insect with its sharp beak. Then, holding on to the head (above), it thrashed it against the branch until it managed to tear away the upper portion from the body and got a first taste of its crunchy meal (below). Beetles have a thick protective sheath, the elytra, over the back portion of the body. This is made up of the hardened forewings, tucked under which is the pair of functioning membranous wings. The other parts of the body have a covering of thick cuticle. So beetles are generally well protected from predators. But not from shrikes! The shrike next tried to crush the headless beetle with its powerful beak (above). But the beetle's elytra proved too hard. With another swift swing it got the elytra detached. The bird then tried to squeeze out the soft tissue and in the process nearly lost its grip on the perch. It continued to crush the thorax with its powerful jaws, pulling at the soft tissues, determined to get to the succulent part. At this point the beetle thorax was totally mangled (above). Swallowing the thoracic portion, it tried to swallow the remaining part but could not succeed (above). It was either too hard or too big. It tried to crush and flatten it further in between its mandibles before finally finishing its meal (below).
Tha above account is by Melinda Chan. All images by Chan Yoke Meng. The beetle was identified with the help of Dr Cheong Loong Fah