This was exactly what Liu Jianzhong a.k.a. Jz was thinking when he stalked a Blue-tailed Bee-eater (Merops philippinus) some weeks back - and documented what it did.

The bee-eater had just had its fill of insects and glided with its wings flapping in slow motion to its favourite perch (above). There, it perched with its wings still held high for some time. Such characteristic “butterfly” display is not unusual among bee-eaters.

Such a display sometimes end with copulation, if there is another bird of the opposite sex present. But in this instance it simply proceeded with its comfort routine.

First, it preened its feathers (above left). Then it fluffed its plumage (above right). All these activities are necessary to keep the feathers in top condition. Then the bird indulged in stretching activities to keep the muscles in top condition and stimulate blood circulation, or so ornithologists believe.

It first stretched both its wings upwards, in a sort of “angel” posture (above). Then it stretched its right wing and right leg together, at the same time fanning its tail feathers (below left). This was followed by the left wing and left leg and similarly fanned its tail feathers (below right).

Finally, it cast a pellet of undigested insect exco-skeleton, etc. (below).

See earlier posts on pellet casting HERE: 1, 2, 3, 4 and 5.

All images by Liu Jianzhong.

This post is a cooperative effort between NaturePixels.org and BESG to bring the study of bird behaviour through photography to a wider audience.

ON 20th December 2007 Tan Gim Cheong sent in an exciting image of a Common Kingfisher (Alcedo atthis) in the act of casting a large pellet.

“Managed to catch this Common Kingfisher casting a pellet, even sent debris flying to the upper left! The pellet is large relative to the size of the bird, for example the Spotted Wood Owl’s pellet is a much smaller percentage of its body size.”

Yes, most birds that eat animal prey cast the indigestible parts like bones, fur, etc after compaction in the gizzard in the form of pellets. Birds that eat insect similarly cast pellets of the exoskeleton, as seen in bee-eaters. Those that eat hairy caterpillars cast pellets of the hairs.

Local birders have always known that raptors and owls regularly cast pellets. Only of late have birders become aware that other birds also cast pellets.

This blog highlighted pellet casting as far back as March 2006 and Jianzhong Liu was kind enough to submit an image of a Blue-tailed Bee-eater (Merops philippinus) doing just that.

Subsequent to this, other bird photographers also managed to catch various species in the act of pellet casting – Blue-tailed Bee-eater (below right), Ruddy Kingfisher (Halcyon coromanda) (below left) and Spotted Wood Owl (Strix seloputo).

It is heartening to know that birders and bird photographers are keeping an eye on bird behaviour when out in the field. After all, birding will always be more enjoyable if we also pay attention to bird behaviour.

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Input an image of Common Kingfisher by Tan Gim Cheong; images of Ruddy Kingfisher and Blue-tailed Kingfisher by Chan Yoke Meng.

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.

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).

Singapore has two species of bee-eater, Blue-tailed Bee-eater (Merops philippinus) and Blue-throated Bee-eater (M. viridis). The former is a very common winter visitor while the latter is a common resident but a rather uncommon winter visitor. These birds, as their names imply, specialise on bees, often caught on the wing. They also eat other insects of the same hymenopteran group as well as other groups of insects. But they seldom eat ground insects.

The bird normally perches on a high vantage point where it can keep a keen lookout for flying insects. Once it spots an insect, it sallies forth, catching and bringing it back to its perch to be processed. This involves striking it against the branch to stun it and rubbing it against a hard surface to remove the sting and venom sac. Once the insect has been properly processed, it is tossed in the air and immediately swallowed.

Bee-eaters regularly regurgitate pellets containing the indigestible remains of the insects they eat. It has been reported that the fresh pellet is blackish and about 1-3 cm long.

In an earlier posting I mentioned witnessing a Blue-tailed Bee-eater (Merops philippinus) regurgitating a pellet. Ardent birder, Cheong Weng Chun was quick to confirm, and so was Jianzhong Liu who sent an image of the bird in the act of pushing out a pellet from its mouth. By any account the image is awesome. I always find it interesting that photographers are the ones who notice and provide evidence of such details, not the normal birdwatchers. Why? Because photographers click, wait to click again and wait some more. And birders aim the binoculars, ID the bird and move away. The latter thus miss the most of the juicy aspects of bird watching. I have said before and I say it again. Birders should seriously think of becoming photographers…

In the meantime I have managed to obtain a series of images of the Blue-tailed Bee-eater caught in the act of casting a pellet. They are displayed here, courtesy of photographers Meng and Melinda Chan. Thank you both for agreeing to share with others your exciting series of images.


Meanwhile Jianzhong Liu has alerted me to a thread in a Taiwan forum on pellet casting by a shorebird.