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Saturday, July 30, 2005

WHAT HAPPENED TO THE YELLOW-VENTED BULBULS' CHICK?

WHAT HAPPENED TO THE YELLOW-VENTED BULBULS' CHICK?

Last month a pair of Yellow-vented Bulbuls (Pycnonotus goiavier) built their nest among the branches of a Dracaena tree by my bedroom window. The convenience of the location led me to keep watch on the activities of the birds every day for the next few weeks. I set up my camera by the window. The curtains helped to shade me from being noticed by the birds. But the birds knew I was around. Every time I looked into the camera, the bird in the nest would face me, beak wide open.

It was an exciting period as I watched them incubating the egg (only one was laid) and looking after the chick.

During incubation, the birds did not sit in the nest continuously. Both parents visited the nest regularly. Each took turns to sit on the egg for about 10 to 15 minutes before flying off. This went on throughout the day. Only towards dusk would one of the birds stay in the nest, to remain there throughout the night. By dawn the duty bird left the nest but one or the other would return for short periods throughout the day. Unfortunately the sexes look alike so I could not distinguish between them.

One morning, 10 days after I spotted the nest, the egg hatched. The day-old blind chick was totally devoid of feathers. It remained flat on the bottom of the nest. There was no sign of the eggshell in the nest or on the ground around. The bird must have dumped it some distance away.

Throughout the day both parents flew in and out of the nest bringing food to feed the newly hatched chick. The chick responded to the parents' presence by opening its beak wide. After the food was transferred to the chick, the parent bird settled down in the nest, to fly off after a short while. Every 10 to 15 minutes one or the other bird flew in to feed the hungry chick. By the third day the chick was fed solid food of various insects and invertebrates. If the piece of food were too big for the chick to swallow, the parent bird would pull it out of the chick's throat and try breaking it into smaller pieces.

The parent birds were seen to constantly peck into the nest, probably removing bits and pieces of food not eaten by the chick. Or was it pecking at the ants in the nest? It was also possible that the bird were eating the excretion of the chick as, according to the literature, this contains undigested food.

One day, I was immediately below the nest when the parent bird noticed my presence. It suddenly took off and landed on the ground some distance away. It pretended to be hurt, flapping it wings to exaggerate its supposedly wounded condition. Naturally when I approached it, the bird moved further away, to subsequently fly off.

Unfortunately, after the chick was only four days old, tragedy struck. I saw the parent bird settling down for the night with the chick. But next morning the chick was nowhere to be seen. The nest was empty. It must have disappeared from the nest sometime during the night. Who or what was responsible, I do not know. Could it be crows? But then there were no crows at night or even during the early morning. Could it be a cat or a rat? Possible. Or a changeable lizard? Maybe, as there were a few around. Or it could be a snake or a squirrel even?

The birds were in shock that morning, flying in and looking puzzled. They took turns returning to the nest, looking around with their beaks wide open and even sitting in the nest for short periods before flying off. This they did for some time before the truth must have dawned on them that the chick was really gone and would not appear ever again. Then they finally left the scene.

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7 Comments:

At 3:48 pm, Blogger WLK said...

It is well known that tropical birds suffer more than 60%, sometimes even more mortality rates due mainly to predation. It is most likely that the bulbul chick could be taken at night by a cat or a rat or even a snake. Perhaps it might be worth the while to put up a video for the night, if the bird nest just outside your window again.

Although the nest has failed, it is important that the information is still logged in the database so that we can eventually calculate the percentage nest failure in Singapore.

 
At 5:48 pm, Blogger YC said...

That's a good idea, setting up a video. I will have to convince myself that it is worth the trouble to learn how to use the video. Thanks, wlk for the suggestion.

 
At 11:30 pm, Blogger Jeremy747 said...

In the late 70's when my father just bought the house in Seletar Hills Est, the small garden in the terrace house came with a 3m tall juniper (i think so. I am only a half baked botanist) tree. The apex of the tree was the favourite perch for the noisy morning wake up call of the yellow vented bulbul. A pair eventually decided to nest there and it became my primary past time for a few weeks after school.

Curious and definitely not contented to let nature take its course. I climbed up and stared point blank at the incubating bird in the nest. Although they fled the nest every time i took a peek. They continued to tend to the eggs.

The chicks finally hatched and I took them out to play with them almost every day and put them back. That was when i first fake injury performance by one of the parents. Facinated, as a 5 year old kid then, of observing this behaviour in person instead of from the TV screen. I continued to torment the parents to see how far they would carry out the performance.

I also noticed that the chicks were also not shy of taking excursions away from the nest even at a young age. I would sometimes find them perched on a branch some distance away from the nest.

In the end, I think my intrusion of privacy was too much for the parents. They built a new nest in the property across the road. And they relocated the two chicks across. How they did it, i really don't know. If the chicks were to do it on foot. It would be two deep drains and several stray cats' journey just to make the 20m trip across. But i am inclined to believe thet the parents carried them across. But I no proof of such a possibility. 5 year old kids aren't so complicated.

 
At 9:41 am, Anonymous Anonymous said...

Hi!I'm an accidental Malaysian birder. Like you, I had the great pleasure of watching a bulbul build its nest right in my sheltered patio, which is not at all and ideal place for a nest. If you are keen, I posted the photo-essay at www.blog.thestar.com.my. Key in "a small miracle" in the contents box. I am glad I found a few morsels of info from your write-up that enlightened me. Like you, I too have many unanswered questions about the babies.

Teresa

 
At 3:51 pm, Anonymous Christine said...

I came across your website while trying to find out at what stage the chick will start to fly. I live around the Upper Bukit Timah area, and there is a yellow-vented bulbul nest in one of my plants in the corridor. I've had the pleasure of tracking the progress -- from egg to chick. There were initially 2 eggs and both hatched into chicks. But on the 4th day after the chicks hatched, I came across one of the chicks on the tiled floor not far from the nest. It was dead and was about the same size as when it first hatched. The surviving chick was still in the nest and had doubled in size. I'm not sure what happened, as I know it was removed from the nest between 9:45AM (when my husband left for work) and 10:30AM (when I went outside). There are no strays in my area, and I've not seen any predatory birds. And it wasn't the folks living next door either. So I can only assume that the parent bird removed it as it was weak, or it had died.

So far, it is the 13th day since the chick hatched, and it's now a fluffy, feathered little thing. The parent bird still comes by a few times a day to feed it, but I have not seen it attempt to fly.

 
At 5:02 pm, Anonymous Anonymous said...

Hi Christine

It was probably the sibling that kicked the chick out of the nest.

Please visit the new site - http://besgroup.talfrynature.com/

 
At 8:49 pm, Anonymous Zoro said...

Hey. I have a yellow-vented bulbul in my house. she/he likes to fly around my house..We dont know its a male or female but my family thought is a female..we put her inside a cage when its time to get her some sleep :). My Elder Brother found her in a basketball court..should be she dropped down from a tree..so my brother take her back n feed her..now she wont run away..even if i open the door widely. she still loves our home. what a weird bird :)

 

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