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Thursday, November 30, 2006

Common Kingfisher: Hovering

Common Kingfisher: Hovering

On the morning of 21st November 2006, KC Tsang was admiring a Common Kingfisher (Alcedo atthis) quietly perching on a branch of a tree. He had his camera setup ready and so took a shot of the bird (above). Then suddenly it flew off and hovered above the ground, “like a helicopter” he wrote (below). The bird then swooped down on the grass below and caught an insect. As KC wrote: “According to my long-time birder friend… this must be a new behaviour.” Well, most kingfishers hunt from a high perch, splash-diving into the water or dropping onto the ground to catch a prey (below). These birds take insects and other invertebrates, crustaceans, fishes, frogs, geckos, snakes and sometimes even small birds. Several species use the technique of hovering to forage but only in the Pied Kingfisher (Ceryle rudis) has the technique been perfected. Lui Jianzhong was kind enough to share his images of a hovering Common Kingfisher taken in Hongkong some time ago. The bird was hovering over the mudflat looking for a potential meal like mudskippers, fishes or shrimps (above and below). Hovering is an energy-intensive activity, achieved by beating the wings more or less horizontally – to provide lift but not thrust. The ability to hover for long periods is advantageous when foraging in areas away from a nearby perch. This means that the bird can maximize its time for hunting, rather than returning to a nearby perch to scan the area.

Our bird specialist R. Subaraj has this to say: "This is not new behaviour! The Common Kingfisher is well known for using this method in addition to fishing from a perch and has been observed and documented hovering on several occasions in Singapore and Malaysia."

Input by KC Tsang and Lui Jianzhong; images by KC (top three) and Jianzhong (bottom two).


Wednesday, November 29, 2006

Of marsh harriers and other exotic species

Of marsh harriers and other exotic species

In an earlier post on Common Moorhen (Gallinula chloropus), it was mentioned that Western Marsh Harriers (Circus aeruginosus) and Steppe Eagles (Aquila nipalensis) were seen above the paddy fields in Malaysia where Allan Teo was observing and photographing the moorhens.

Yong Ding Li made a pertinent comment, “Take note on the point about Western Marsh Harrier... It is actually a very very rare migrant to South East Asia and more so for Singapore (I suspect only one recent record and even then it is probably mis-IDed many times). Instead here it is replaced by Eastern Marsh Harriers (Circus spilonotus). In the oriental region, western is only regular in the subcontinent, occuring in wetlands and plains of places like Rann of Kutch, Bharatpur where it can be rather common.

However, R. Subaraj has this to say: “To me, the birds in the photo (above) look like a young female Western Marsh Harrier (on left) and a juvenile Steppe Eagle.

“With regards to Ding Li's statement regarding the status of marsh harriers here, it is a little out-dated. Until 2005, he is right, as reflected in Robson's guide. It was common in Myanmar but rare or a vagrant to Thailand and Peninsula Malaysia... no confirmed Singapore records! At the end of 2005, both Western and Eastern Marsh Harriers were reported from Changi Reclaimed Land and in the weeks to follow, several birders had visited the site and confirmed the presence of both species... with as many as 3 Westerns.

“Being a skeptic myself, I visited the area a few times during that period and personally confirmed at least three Western Marsh Harriers, along with a few Eastern, with excellent views. Reliable collegues and visiting birders, with me or independently, concurred. Hence, the Western Marsh Harrier does occur in Singapore as a vagrant, at least. “It is worth monitoring our area for the next few months to see if they visit again and become a regular occurrence... or if the last season was just unusual. In the last two decades, unexpected raptors have kept turning up in Singapore. Himalayan Griffon (Gyps himalayensis) (above) and Lesser Kestrel (Falco naumanni) are two others that fall into a similar category as the Western Marsh Harrier... birds that formerly only occurred no nearer than India and Myanmar. Other unexpected raptors that have turned up include Oriental Hobby and Jerdon's Baza (Aviceda jerdoni)... normally sedentary species found no closer than the northern half of Malaysia, where they were considered rare.

“So what is going on! Why are these species suddenly turning up in Singapore? Perhaps it is the changing climate conditions? Or the continued deforestation and/or persecution of birds further north and south of us? Perhaps a bit of both!

“Other factors that certainly contribute are the superior optics available, the better field guides and identification books and the increased number of observers covering various parts of our nation. The digital photography age is also making a significant difference in confirming species.

“Finally, and equally significantly, the shrinking habitats available due to development means that birds have less choices if they turn up in Singapore and birders have a better chance of finding them!”

Input by Yong Ding Li and R. Subaraj; images by Allan Teo (top) and Wang Luan Keng (bottom).


Tuesday, November 28, 2006

Peregrine Falcon feasting on a Black-naped Oriole

Peregrine Falcon feasting on a Black-naped Oriole

Cheong Weng Chun was going through some of his old bird images when he came across a composite image of a Peregrine Falcon (Falco peregrinus) feasting on a Black-naped Oriole (Oriolus chinensis) (left). The images were taken on 7th March 2004 in Port Dickson when he was just beginning to take an interest in digiscoping birds. He shared the images with like-minded birders then and showed the composite images in the BESG’s e-loop a few days ago.

Through the courtesy of Weng Chun, we are presenting his images highlighting the stages of the falcon's feast, first preparing its catch and then feasting on it…

Peregrine Falcon feeds exclusively on birds like doves, sparrows, waterfowls, feral pigeons and songbirds. It is fast and agile in the air, being the world’s swiftest bird, having the ability to reach a speed exceeding 300 km/h when pursuing a prey. It hunts birds in mid-air, first hitting the prey at great speed with its foot, then swooping back to catch it. The bird has a conspicuous tomial tooth, a sharp triangular-shaped downward pointing projection found at the outer edge of the upper mandible near the curved part of the beak (see above). This sharp “tooth” is thought to serve mainly in the killing of prey by breaking the victim’s neck. In the above image the prey was brought back to its favourite perch to be eaten. The dead bird was first decapitated and then carefully plucked of its feathers (below). With the help of its tomial tooth and powerful bill, the falcon tore through the featherless prey and began its feast (below).

In about 30 minutes or so all the flesh had disappeared from the dead bird and the falcon began to pick at the bones (below). Soon even the bones were picked clean...

...leaving only a satiated falcon (below).
Input and images courtesy of Cheong Weng Chun


Monday, November 27, 2006

Oriental Pied Hornbill courtship

Oriental Pied Hornbill courtship

A pair of Oriental Pied Hornbill (Anthracoceros albirostris) was seen at Changi Village around 5.45 pm in early October 2006 in a courtship ritual. The pair was perching on the branch of one of the old angsana trees (Pterocarpus indicus) lining the main road. The male had just caught a gecko, which, in its struggle to get free, lost its tail (above). The bird approached his mate and offered the gecko to her. The mate appeared to accept, opening her bill, but apparently he was just teasing her (above and below).The male bird trotted off along the branch, soon followed by the female. He then flew off to a nearby tree trunk with a cavity that developed as a result of faulty pruning of a branch. There he waited for some time with the gecko still in his bill. He then went through the motion of placing the gecko inside the cavity a few times without getting the female to fly over (below). After some time trying to entice her to come over to check on the cavity, as is usual with hornbills, he flew off to a nearby branch to eat the morsel himself. See also the courtship between a Great Hornbill (Buceros bicronis) and a Rhinoceros Hornbill (B. rhinoceros) here.

Input and images by Meng and Melinda Chan.


Sunday, November 26, 2006

Why do birds yawn?

Why do birds yawn?

James Heng brought back this account from his birding trip to Bach Ma National Park, Vietnam earlier this year:

“The ranger informed me about this pair of Brown Fish Owls (Ketupa zeylonensis), a cousin of our Buffy Fish Owl ( Ketupa ketupu) (left), that has been nesting at the same pillar at the gates of the park for several years.

“The pillar is about 4 m high, and is beside the road leading up to the summit. A small number of people use the road so the owls tend to hide amongst the large leaves of the trees to avoid detection. I've not seen them yawn even once when they are wary of people at that spot.

“But by mid-morning though, one would fly to a nearby branch about 3 storeys high where it feels safe. On that perch, it's eyelids will tend to droop and it begins a whole series of yawns before dozing off.

“After watching it yawn several times, I began to yawn too! It was really amusing.

“Hmm, wonder if the reverse it true - if we yawn repeatedly at them, would they yawn too?”

Now why do birds yawn?

Yawning may sooth an itchy throat. Maybe they yawn for the same reason we do, because they are sleepy. Or there is a need for oxygen intake. The yawning is most often triggered when one is tired. Yawning is common at night as our bodies prepare for sleep. The presence of foreign materials in the throat may induce yawn-like actions.

There are those who believe that yawning in birds help remove excess heat.

Very little has been studied on the sleeping habits of birds. We generally assume that, like people and other warm-blooded animals, they sleep when they are tired and full of food. And when they wake up, they yawn and stretch before flying off to forage.

Now, is the Blue-throated Bee-eater (Merops viridis) on the left yawning? Most probably not. Maybe it is casting a pellet?

If you need to see a Buffy Fish Owl yawning, go to our earlier posting.

Input by James Heng; top image by YC, bottom image by Johnny Wee.


Saturday, November 25, 2006

Do birds sleep?

Do birds sleep?

Yes, birds do sleep. Like all warm-blooded animals, they sleep when they are tired and full of food. After all, most birds cannot see well at night. Only a few, like the owls, have large eyes specially adapted for night vision. When they sleep their toes automatically lock tight, thus preventing them from falling while asleep. The above image of the Common Iora (Aegithina tiphia) snug in its nest, was taken by Cheong Weng Chun at night. Although it shows the back view, I am sure the bird was fast asleep. Many species like mynas, crows, starlings, Pacific Swallow (Hirundo tahitica) and Barn Swallow (Hirundo rustica) (above) come together in the evening before dusk to roost on the branches of certain trees. During this period they generate much noise as they squabble over their favourite perch before settling down for the night. Although asleep, these birds are alert and will suddenly move off amidst much noise if disturbed. Early next morning, just before dawn, they wake up, yawn, stretch, refreshed but hungry. Then off they fly to forage.

Hole nesters like woodpeckers usually sleep in tree cavities. Ground nesters sleep on or near the ground.

Obviously nocturnal birds like owls and nightjars sleep during the day.

And many birds "talk" in their sleep and some even sing on moonlit nights.

Input by YC, image above by Cheong Weng Chun, below by YC.


Friday, November 24, 2006

Black-naped Oriole manipulating a cocoon

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 (, 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.


Thursday, November 23, 2006

Laughing Kookaburra

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.


Wednesday, November 22, 2006

Common Moorhen

Common Moorhen

The Common Moorhen (Gallinula chloropus) is a bird of wetlands. It is easily recognised from its red bill and prominent shield against a blackish plumage (above). The juvenile is dark brown and pale below, with an olive bill and without the prominent shield (below). Allan Teo recently spent over three hours in a rice field in Malaysia observing a family of Common Moorhens. Enclosed within his cameo sheet hide and comfortably seated on his field chair, he set up his equipment and waited patiently for the family to reappear. His camera was directed at the exact spot where the birds were earlier foraging, but went into hiding among the rice plants when he appeared. The birds benefitted from the limited shelter provided by the rice plants but the shelter was not dense to totally cover them up. The birds were shy and skittish, moving between the narrow spaces where the plants were sparse and swimming in small pools where the plants were absent or trampled (above).

The parents were always on the lookout for danger, especially from the many raptors that roamed the sky above. Besides, there were also other predators among the paddy.

As Allan recounts, “It took about 20 minutes from my arrival and installation of the hide before the parent birds reappeared. They cautiously emerged from between the rice plants. They swam around in the pool of water for 5-10 minutes before they called for the chicks to come out from among the rice plants.”
All the time the chicks stayed hidden among the tall rice plants, staying very still. They were not visible at all. Cautiously, they emerged, entering the water only when the parents coaxed them (above). Every 10-15 minutes the chicks would touch beaks with the parents, probably for re-assurance. Then suddenly from above, there appeared a black kite with its head looking downwards at its flight path (above). It must have spotted the moorhens. Immediately the family scrambled for cover and disappeared form sight. Large migratory raptors like Western Marsh Harrier (Circus aeruginosus) and Steppe Eagle (Aquila nipalensis) can easily take an adult moorhen. In the above image, the former is clutching a bird in its talons with the latter trying to snatch it or to make it drop its prey. There were also White-bellied Sea Eagles (Haliaeetus leucogaster) above, patrolling the area over the rice fields the year round. These birds have sharp eyes and can easily spot the moorhens.

When the coast was clear, the cycle repeated itself - the parents came out alone, tested the waters after which they called the chicks out to the water and performed the re-assurance ritual of touching beaks.
Moorhen chicks are precocial, meaning that they hatch in a relatively developed state, with the body covered with down and the eyes open (above). They leave the nest soon after hatching, usually after one to two days, swimming by the third and diving by the eighth. Both parents feed and care for the chicks. Immature birds of the previous brood as well as adults of the group may also chip in. Brooding may continue until about 14 days. The chicks can feed by themselves around 21-25 days but continue to be fed for up to 45 days. They fledge at 45-50 days.

The chick above is one of four from a family of the moorhen Allan spotted. There were at least three families in all.

Around the end of October 2006 Cheong Weng Chun also encountered Common Moorhens in the paddy fields of Malacca, Malaysia (below). The parent birds were feeding the chicks with apple snails that were collected from the shallow areas. Only small snails were selected, the larger ones were not taken. Weng Chun thinks that the shell of the smaller snails is probably softer than that of the bigger ones.

Input by Allan Teo and Cheong Weng Chun. Images by Weng Chun (top two and bottom) and Allan (the rest).


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