Our earlier post by Francis Yap documented a Banded-bay Cuckoo (Cacomantis sonneratii) fledgling being fed by an adult Common Iora (Aegithina tiphia) in photographs LINK.
Francis has now documented a video of a similar feeding (above). Taken at the same location but about a month apart, this is a different Banded-bay Cuckoo that “looked a bit younger at the time of the video capture compared to the previous cuckoo that was photographed. This was based on it’s appearance and the fact that the previous cuckoo was much more active in flying about. I have no way of determining the age of the Common Iora host. This goes to prove that the Banded Bay Cuckoos have been pretty successful in parasitising the Common Ioras [in Singapore] this year.”
The video has been able to show certain behavioural traits that images fail to show. For one, it is noted that the fledgling vibrates only one wing and not both whenever the oriole approaches it with food (above). When the oriole approaches from the left, the fledgling vibrates its left wing. When the foster parent approaches from the right the cuckoo vibrates its right wing.
Another trait the video clearly shows is that the fledgling remains where it is with bill agape whenever the iora arrives with food. The iora then moves in to place the food into the gaping red throat. Only then does the fledgling lunges forward, hoping for a second feed (above). And invariably the adult moves aside or flies off.
This again shows the superiority of the video over the digital camera in the study of bird behaviour LINK.