The Yellow-vented Bulbul’s (Pycnonotus goiavier) was 5 days old on 8th June 2015. The feeding behavior of the adults was video recorded from 1410-1930 hours from the bedroom. The clips were subsequently analysed to determine the regularity of the visits and the length of time spent inside the nest by each adult on their visits.
As with the 2 days old chick LINK, the adults arrived by two routes. Flying from the garden towards the nesting tree, it would make a sudden u-turn to enter the nest from the left – viewing from the bedroom window. Alternately, the adult may fly directly to enter the nest from the right.
The usual time spent was 10-20 seconds, just to pass on the insects. Entering the nest from the right involved perching on a branch to feed the chick. Using the other route, the adult would perch on the edge of the nest to feed the chick. Only via this route would it actually enter the nest after feeding the chick – and remain there for some time, the longest period being 18 minutes.
As in the case of the 2 days old chick, the adults were not seen removing and disposing any faecal sacs after the feeding – see HERE. Bulbul chicks dispose of their wastes packaged in gelatinous sacs. The ejection of these sacs was not seen due to the foliage around the nest. It is assumed that the adults must have eaten them. After all, at 5 days, the chick’s digestive system most probably was not fully functional as to extract all the nutrients from the food fed to it.
At 5 days old, this chick was fed 16.1 times per hour, based on the number of feeding by the two adults during the monitoring period of about five hours. This compares to the mean of 5.6 feeding per hour in the case of the 2 days old chick. Obviously the younger chick needed less food, thus the adults did not have to work too hard to feed them.
The last feed came towards dusk after which the adult settled in the nest for the night.
I have seen some nests where the younger chick is badly harassed by its older sibling. I have removed an older sibling when I noticed the younger one having a multitude of bruises, some bleeding, around its head. It was also hanging precariously on a poorly made nest and the older one was definitely doing its best to get whatever food that was coming from the parents.
I have also seen a nest where one chick was sitting over the rotting carcass of its sibling. That one I have a bath and put back into the nest after the nest too was drenched with some water. This chick was seen leaving its nest quite early. Probably due to my actions. But it managed to get a top a taller tree. The last time I saw the bird, it was in full flight and chasing its parents from tree to tree.
The older sibling even goes to the extent of pushing the younger out of the nest…
Bird Ecology Study Group Nesting bulbul: 4. Pre-feeding behaviour
[…] (Pycnonotus goiavier) were always careful when flying into the nest to feed the chick HERE and HERE. They do not fly in directly but land some distance […]