The Yellow-vented Bulbul’s (Pycnonotus goiavier) nest in front of my bedroom window LINK was constructed such that the side facing the garden was well camouflaged (above). The side that faced the window was more open and this was where most of the time the birds flew into the nest (below).
Whenever I was in the garden and an adult was nearby, it gave out a sort of warning(?) call while keeping a close watch on me (below).
On the morning of 24th May 2015 the nest was examined with the aid of a mirror after the adult left. Two eggs were inside. One egg hatched 11 days later. The adults then started feeding the chick. By afternoon the second egg disappeared. There was no trace of the shell or the chick around the garden. Assuming the second egg hatched, the shell would have been removed by the adult. But then what happened to the newly hatched chick? This would have to remain a mystery.
Video surveillance was made on 5th June between 1320-1440 hours when the chick was two days old. There were a total of 22 feeding visits by the adults, each lasting between a few seconds to a few minutes, the longest being a single case of 8 minutes 20 seconds. The timing between one adult leaving and another entering the nest was from almost immediate to about 7 minutes later. In one instance an adult entered the nest before the one inside was ready to leave, resulting in a sort of near “collision” (near end of video).
The adults entered the nest from the garden, flying towards the left or right, to make a sudden turn to reach the nest (see video). Rarely did the adults flew from above into the nest.
Assuming the adults flew into the nest one after another, from the sequence it would appear that one had the tendency to sit in the nest to clean up the mess after passing on the food. The other would deliver the food perching from a nearby branch after which it flew off. However, this is only a speculation.
None of the adults was seen removing the faecal sac after feeding LINK. In a number of instances the adults were seen swallowing something after feeding. Most probably they were eating stray pieces of prey or even swallowing the faecal sac. Young chicks do not have an efficient digestive system and a certain amount of food passes out undigested. Thus the adults have been reported eating the faecal sacs.
Bird Ecology Study Group Nesting bulbul: 4. Pre-feeding behaviour
[…] Bulbuls (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 […]