View Full Version : The Koel’s interesting feeding behaviour – favouring the farmers

Samrat Sarkar
24-12-2016, 08:06 PM
The significance of the pointed gourd (Trichosanthes dioica) fields wanes just at the onset of the winter seasons to the owners of the fields. The land owners, who are the cultivators as well pay no attention to the fields and wait for the next cultivating season. The makeshift scaffoldings for the pointed gourd plants weaken at the end of the year-long cultivation. The output strength of the pointed gourd plants diminishes as well. Also, the demand of the pointed gourds to the people starts coming down.The farmers lose interest for the few pointed gourds left unplucked in the fields.

Incidentally, some pointed gourds after beeing left in the scaffolding for a long time, ripen and turn orange. That is when a number of types of birds start visitingthe field being allured by the ripe pointed gourds. And so, these pointed gourd fields of our village turn out to be sort of ‘bird watching spots’.

Many types of Munias frequent the pointed gourd fields to feed on the seeds of grass that grow below the scaffolding as the ground remains unattended for a long period of time. Some other birds, such as Wagtail, Olive-backed Pipit, Paddyfield Pipit, Jungle Babbler etc. come in search of small insects that live and thrive below the thick growth of the layer of grasses. The important birds among those which come to the fields in search of ripe pointed gourds are Bulbuls, Mynas, Starlings, and mostly, Asian Koels.

Asian Koel flying over pointed gourd field

Samrat Sarkar
24-12-2016, 08:10 PM
It has come to my notice that the way the Asian Koels feed on the ripe pointed gourds is most fascinating among that of all other birds. That is in the sense that, while other birds, such as Bulbuls, starlings etc. feed on the fleshy and juicy parts of the ripe pointed gourds by small bites, the Asian Koels do that in a completely different way.

Red vented Bulbul feeding ripe gourd by small bites.

Samrat Sarkar
24-12-2016, 08:12 PM
At first they sit on the scaffolding patiently and look around to see where there are ripe pointed gourds within its reach. It is a bit troublesome for a large bird like it to go to the narrow space below the scaffoldings and then to pluck a whole pointed gourd from there. So it is very important for it to see that the pointed gourd it wants to collect is in a favourable place.

Samrat Sarkar
24-12-2016, 08:14 PM
Once it locates and chooses a pointed gourd he tears it whole from the plant with its beak.

Samrat Sarkar
24-12-2016, 08:16 PM
It never starts eating just after collecting the gourd unlike the Bulbuls, starlings and other birds do. It neither starts pecking the gourds as it hangs downwards in the scaffolding. They are rather more interested to swallow one gourd whole at a time.

Samrat Sarkar
24-12-2016, 08:17 PM
It flings the gourd in the air so as to swallow it whole.

Samrat Sarkar
24-12-2016, 08:19 PM
The stint of a few moments of observation ended there but the incidence of swallowing whole pointed gourds by the Asian Koels is one of the unique characteristics of them. The ripe pointed gourd as seen in the pictures here being eaten by the Asian Koel is about 30 mm. We can arrive to some conclusions from the observations.

Samrat Sarkar
24-12-2016, 08:23 PM
The conclusions are -

1. The throat gap of the Asian Koels is larger than that of the other birds. Therefore it is not difficult for them to swallow the pointed gourds whole.

2. Not only the ripe fruits, they can swallow quite large Hairy caterpillars as well whole.

3. But Asian Koels have no role in helping the pointed gourd plants to thrive.

4. One of the main harmful insects for the pointed gourds are the fruit flies. They lay eggs on the partly eaten ripe pointed gourgs.

Fruit flies on partly eaten ripe gourd

Samrat Sarkar
24-12-2016, 08:28 PM
Their larvae and pupae live and grow on the flesh of the ripe pointed gourds and turn into full grown fruit flies. As the other birds peck on the pointed gourds to eat them it becomes very much possible for the fruit flies to lay eggs on these partly eaten gourds. But the Asian Koels decrease this possibility to some extent as they swallow the fruit whole. Therefore they help the farmers in this respect. In this way a well known bird has been favouring the farmers through a very less known feeding habit unawarely.

References –

This was first published on 15 March 1959 in The Sunday Statesman.

B. Bird ecology study group. Website - www.besgroup.org

Written in bengali and Photographed by Samrat Sarkar.
Translation into english by Biswajit Debnath

Equipment used – Canon EOS 7D + Canon 500mm f4 IS II USM L + Monopod and Olympus OMD EM-1 + Zuiko 12-40mm f2.8 PRO.
Place of observation – Nadia, West Bengal.
Month of observation – December, 2016

Larvae of fruit fly in ripe gourd