Malayan Whistling Thrush: 4. Preparing to fledge
Posted by BESG on 4 April 08, Friday
Contributed by Allan Teo & YC
The chicks of the Malayan Whistling Thrush (Myophonus robinsoni) had grown quite a lot by 27th March 2008. Their wings feathers and muscles appeared fully developed and they had been flapping and stretching their wings all the time.
Allan Teo was first to notice that the adults were preparing the chicks for fledging. The adults were arriving less frequently with food. At times one chick was fed while the other had to wait 10 minutes or longer for its turn. Other times they were simply teasing the chicks, not feeding them, just approaching and then flying off.
In one incident, an adult appeared with its bill stuffed with what looked like worms. It offered them to a chick, to immediately withdraw. (It was not clear whether it ate the food or fed the chick with it.) The adult then moved into the nest and huddled with the two chicks.
It was then that the other adult arrived, perching some distance away on the beam (above left). The chicks immediately started begging and it fed the chicks with the first adult still in the nest (above right). Second adult stayed for a few seconds before leaving. It appeared again a few seconds later to again feed the chicks. The first adult remained in the nest all this time. This shows that both parents take part in feeding the chicks.
The chicks responded to the decreased feeding and noisy encouragements by the adults to fledge by standing along the nest edge and looking downwards, where on of the adults was probably there calling. In the image below (left), note the presence of an adult on the wall in the background towards the top left.
To encourage the chicks further, an adult regularly joined them in the nest, either after feeding or arriving without feeding. It then huddled over one or the other, with the chick looking downwards – as if to encourage it to fledge.
The coaxing went on for the next few days at a heightened intensity. After a few sessions of enticing the chicks with food and not actually feeding, an adult would arrive to actually feed (top right). By late evening an adult would invariable arrive at the nest to prepare to settle down for the night.
As the days went by, the chicks grew bigger and their wings more powerful. But still they remained in the nest. They perched along the nest edge, they even moved backwards to nearly tumble from the side, they got one of their legs outside the nest… still they remained in the nest (below).
The chicks became more active, moving around the nest, preening, flapping or stretching their wings and calling to be fed. They looked down, side or up, following the movement of one or the other of the adults. Again, an adult may enter the nest and huddle with the chicks, even straddling one as if to encourage it to fly off.
By 31st March, it had been five days of continuous encouragement with no results. The chicks had by then grown a lot and were bigger. Both filled the nest and there was not enough room for the adult. At night, while the chicks slept in the nest, the adult had to sleep most of the time on the perch by the nest (below).
It was observed that at times the adult would sleep on the perch, standing on one leg. This was probably to conserve heat, the temperature inside the warehouse was around 16-17 Degrees Celsius.
For earlier entries on the Malayan Whistling Thrush, please see “Related Posts” below.
YC would like to thank Allan for giving him access to the video recordings of the nesting; Allan gratefully acknowledges the family of Shum Yip Leong for permission to install the video camera within their premise and for generously contributing to substantial bandwidth support.
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