In Pink-necked Green Pigeons both parent birds help in egg incubation and care of the nestlings. The male takes on the day shift, arriving at the nest at around 8 am. He stays in the nest all day, never leaving unless disturbed. The female arrives at around 5 pm and stays in the nest the entire night. Arrivals and departures may be delayed by up to 1.5 hours, especially when the birds detect people around. Like nosy photographers or birdwatchers hidden behind a screen some distance away.
Shift change is the most exciting moment. Usually the bird in the nest becomes slightly excited and moves around a bit when its partner is nearby. Sometimes there is soft gurgling vocalisation from either party. Then suddenly a bird flies in with a distinct flapping of wings to join the other in the nest. The latter moves slightly away to allow the former to sit in the nest before flying off. At times when people are around, the bird may fly in to land on a nearby branch, to move slowly towards the nest as the other bird flies off. Or the bird in the nest may suddenly fly off, the other flying in a few seconds later.
During egg incubation the bird sits quietly in the nest all the time. After the eggs are hatched the parent birds similarly sit quietly but the nestlings are always moving about. Most times the latter would pester the parent in the nest for food. This they do by pecking the parent around the neck area. The parent responds by opening its beak to allow the nestling to poke its beak in to receive the liquid crop milk. During this transfer of food, both necks may twist around somewhat until the transfer is complete. Food transfer occurs at intervals and may again be seen just before the bird leaves the nest. If not, the arriving bird will have to feed the nestlings.
Such a method of feeding allows for the parent birds to remain in the nest all the time, thus providing 24 hours protection to the nestlings. This is sharply contrasted to those birds that need to seek out fruits and insects to feed the nestlings. The nestlings of the Yellow-vented Bulbuls (Pycnonotus goiavier) are left alone for varying periods of time when the parents are away foraging.
Image shows the male just after arriving and the female just before departing, together with one nestling.
7th December 2005