The Calls of the Asian Koel

on 1st February 2012

“While I have no particular liking for the Asian Koel (Eudynamys scolopacea), I am always fascinated by their behaviour. Being a brood parasite and by selecting the House Crow (Corvus splendens) as the host – which even attack human being when they perceive their nests or young to be in danger – they risk their lives while attempting to lay eggs in the crow nests.

“They are many of them around my area. In spite of the crow population being drastically reduced through Govt intervention, it doesn’t seem to have any corresponding effect on the number of koels. They are easy to locate, helped by their relatively large size, tendency to stay at the same spot for long periods, and above all, extremely loud vocalisation.

“Below is a collection of some of my videos and sound clips, mostly of their vocalisation, with my comments and interpretation of the meanings:

“This is a video of the koel’s vocalisation in a trumpet tree (Tabebuia rosea) (above, recorded on 20th Dec 2010 at about 9.30 am). It is a well known repetitive, usually rising in pitch, of an immature male call in the early stage of adulthood. This is heard in the wee hours of the morning, dusk and throughout the day. As the young male is left on its own by the parents (after all they are of different kinds), I believe this is the ‘beacon’ to advertise its location and well being. Some months back I could hear three of them in different locations within a radius of 500m (birds-eye view from my 4th storey apartment on elevated ground). Although there are several more of the adult males here, I don’t hear them making this call. As the young adults mature and become more independent, the frequency and urgency of the calls dropped. Now I only hear one occasionally and it’s much muted.

“I have also observed that the male makes this call while in the vicinity of some nesting crows without provoking any response from the later. This reinforce my perception that they are not sexually matured and pose no threat. Alternatively, it could mean that the male is part of the family.

“Back to the video, the second part shows the gwo-gwo-gwo vocalisation (below, recorded on 21 Apr 2011 at about 9 am). This is the usual response to the sighting of crows, which came about 20 minutes later in this episode.

“This is a video of what looks like an immature female vocalising in an African mahogany (Khaya grandifolia). It was responding to some crows (its parents perhaps). The video also shows how the bird fluff up its chest and abdomen feathers just before defecating. The call is slightly different from that of the adult female which is repeated at a faster tempo (see 7 & 8 below).

3) Female Juvenile call HERE (recorded on 16th March 2010 at about 4.45 pm).

“The first time I came across the soft, harsh call of a juvenile some years ago, I mistook it for the noise made by a cat. Over time I managed to trace one to a female juvenile in a golden shower (Cassia fistula) (left). It was alone around the swimming pool area in my condo. It probably vocalised in distress because I was searching for it from tree to tree. From my observation, this call is made only by the juvenile female and not the juvenile male.

4) Male koel’s call HERE (recorded on 5th April 2010 at about 7.15 pm).

“This gwo-gwo-gwo vocalisation is a typical response to the sight of crows, or when the male is disturbed by loud noises such as passing motorcycles, siren, responding to other Koel or my sight.

5) Male koel call HERE (recorded on 9th April 2010 at about 5.45 pm).

“This is the typical soft male koel vocalisation made in the company of another male or female. Till today I am still puzzled by this behaviour. It doesn’t look like confrontation to me, but more like friendly “banter”.

6) Fright/distress call HERE (recorded on 20th March 2010 at about 9.30 am).

“This is a distress call made by the male when it is chased by the crow. For this recording, I have induced the call by knocking hard on the tree trunk in which Koel was sighted.

7) Duet of male and female HERE (attached Duet Male Female Koel.mp3 recorded on 2 May 2009 at about 6 pm)

“The calls of a male and a female in the same tree. Again I have induced the calls by knocking hard on the tree trunk.

8) Duet of Two Females HERE (attached Duet Female Koel.mp3 recorded on 12 Dec 2010 at about 6.30 pm).

“One female was in a Sea Apple (Syzygium grande) slightly to my right and the other one in a Brown Heart (Andira inermis) on my left. As I approached they called out loudly. This was probably a territorial call targeting me. If you listen carefully you can hear a third one responding some distance away.

9) Cacophony of Koels HERE (attached Koel Cacophony.mp3 recorded on 12 Feb 2009 at about 7 pm).

“It was a cold windy evening when this was recorded. The chorus happens here frequently. By its sheer loudness I think it would have caused great distress to other roosting birds nearby.

10) A ‘synthesis’ call HERE (attached Koel woowoo.mp3).

“There is a rarely heard soft male call which I have been unable to capture. It sounds like woo-woo which is very similar to the first syllable of the ko-el call repeated quickly. I have used the Audacity Digital Audio Editor to give an idea how the call sounds like. If anyone has an actual recording please share.

11) Addendum: The Koel soft call (10) which I had been unable to capture, this morning (24th January) I manged to record it while looking out for some of the Red Jungle Fowls that had migrated to my condo from Sin Ming Ave about a month ago HERE.

“Attached is the ‘cleaned up’ sound clip Koel_woowoo2.mp3 . In the recording, a Red Jungle Fowl is first heard calling. Before its crowing ended, the Koel began and vocalised 3 times. This Koel call is only heard when I am very near to one, invariably in a tree above me.”

Sun Chong Hong
12th January 2012

If you like this post please tap on the Like button at the left bottom of page. Any views and opinions expressed in this article are solely those of the authors/contributors, and are not endorsed by the Lee Kong Chian Natural History Museum (LKCNHM, NUS) or its affiliated institutions. Readers are encouraged to use their discretion before making any decisions or judgements based on the information presented.

YC Wee

Dr Wee played a significant role as a green advocate in Singapore through his extensive involvement in various organizations and committees: as Secretary and Chairman for the Malayan Nature Society (Singapore Branch), and with the Nature Society (Singapore) as founding President (1978-1995). He has also served in the Nature Reserve Board (1987-1989), Nature Reserves Committee (1990-1996), National Council on the Environment/Singapore Environment Council (1992-1996), Work-Group on Nature Conservation (1992) and Inter-Varsity Council on the Environment (1995-1997). He is Patron of the Singapore Gardening Society and was appointed Honorary Museum Associate of the Lee Kong Chian Natural History Museum (LKCNHM) in 2012. In 2005, Dr Wee started the Bird Ecology Study Group. With more than 6,000 entries, the website has become a valuable resource consulted by students, birdwatchers and researchers locally and internationally. The views and opinions expressed in this article are his own, and do not represent those of LKCNHM, the National University of Singapore or its affiliated institutions.

Other posts by YC Wee

5 Responses

  1. Have you noticed communicating Asian koels? Sometimes when a male makes Ku….oooo s it is replied by a similar call from some far away place?
    I never had the opportunity to see the other bird.
    Besides never have I heard a female making Ku…ooo s but the usual short shrills. So I think it is likely a male. It is its mating season now, so I wonder what can this communication b/w the males signify?

    Did you have similar encounter and did you observe the other bird?

  2. I think it’s just a way to communicate and make sure they are not in the own territory , I am Reading this because there is a tree top just 4 meters away from
    My bedroom window on the top floor . It’s not fun waking almost everyday at 5am. I’m trying to evict them !

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