End of the Koel Saga

To: 'Canberra Birds' <>
Subject: End of the Koel Saga
From: Philip Veerman <>
Date: Mon, 2 Mar 2020 00:57:46 +0000

Thanks for the extra information. And for John’s addition to the story just now, that the adult male Koel appears to show a strong interest in the juvenile. Yes adult Koels show lots of interactions, so it can be that there is an interest there. Could it be that this adult male mistakes it for an adult female? That is a long shot but possible. As I read John’s story, the interest is one sided (not that the juvenile is seeking out the adult male). Anyway for now can only take it on board as an interesting story.  


I still think Canberra is a special situation in regard to these birds. If there is more than enough food, then yes may be sensible that young birds can tolerate each other. Actually given the parasitic habit and that for the strategy to work, parasites are typically uncommon, it is likely that in evolutionary time, young birds normally had little opportunity to be in the presence of others of their species. So there may have been no benefit in young cuckoos evolving any particular behaviour towards others. Thus whilst they probably have little or no benefit in evolving any social attraction, once they have grown past the first instinctive behaviour to dispose of any nest competitors and grown up, they may equally have had no benefit in evolving any aggression…….. That can be a better conclusion to my thoughts of yesterday. Whether there are any additional pressures directing behaviour is an extra set of ideas.


Of course John’s line that:  It is not hard to propose an evolutionary mechanism. Such a mechanism would go something like this: young Koels who associate with adult Koels before migration have a better survival rate than those who do not associate with adult Koels and a higher percentage of them go on to breed.” This makes perfect sense if correct although the statistical difference would surely be very small. However does that happen?


As for being taken into care, two ideas: I don’t know each (or any) story. I just suggest that because of the way they behave and call and where they perch and they appear to not have obvious parents taking care of them, that they are far more susceptible than are many other birds, to being picked up by people who don’t know what they are and who will not realise that is what is happening and miss the likely fact that they are actually being cared for by birds that don’t look like parents. Thus I suspect in many cases they should have been left where they are (or returned if it can be done promptly).


Or their foster parents have stopped feeding them, as part of their adaptation technique at a stage where the young Koel may survive, or not, on its own merits, and by rescuing these birds, people are very likely interfering with a natural evolutionary process of how these species progress in their “arms race”.




From: [
Sent: Monday, 2 March, 2020 8:15 AM
To: 'Philip Veerman'; 'Canberra Birds'
Subject: RE: [canberrabirds] End of the Koel Saga


Philip, both from my own observations and from others I have published in my CBN summaries, there are sufficient examples of 2 or more Koel fledglings in close proximity, with in a number of cases two being together for days.  Also in the yet unpublished paper summarising the 2018-2019 season Diana White had three in her and her neighbours gardens in Narrabundah on one occasion, and in the following days 2 of these 3 were often heard or observed at the same time.   Pete Cranston had 3 together in the same tree less than 2 m apart in O’Connor on one occasion, then 2 of them stayed in his garden area for about 3 weeks.


So Koel fledglings certainly tolerate/associate with each other, I can recall no sign of aggression personally or through any of my correspondence with other observers.


There are also examples of Koel fledglings taken into wildlife care, for example, the final 2 entries in Table 4 of my CBN ( 43(3) 274-289 (2018) paper (in which you will also find the references to my other papers).  In the last paragraph of Section 5.6 of this paper, I suggested they were late leaving fledglings which had come to grief during their journey N.  In 2018-2019 Marg Peachey  gave me another 6 examples, and there have also been some this season.  I see no reason why they should not need to be taken into care the same as many other species’ fledglings often need to.


Jack Holland


From: Philip Veerman <>
Sent: Sunday, 1 March 2020 5:45 PM
To: 'John Harris' <>; 'Canberra Birds' <>
Subject: RE: [canberrabirds] End of the Koel Saga


Yes John,


Thanks for your answer, though I feel that by semi reluctantly, following through I am at high risk of being interpreted as being both repetitive and excessive. And understandably because, sorry to me, most of the following is self evident. Some might still be interested. If not, well ignore it.


I submit that the information available is that Koels are parasitic cuckoos. Most of them live mainly solitary lives (apart from adults in the breeding season). Under normal circumstances and presumably for millions of years, cuckoos have struck upon an extraordinary system in which eggs are laid in a host nest and the parents have nil further involvement with them. Thus their whole strategy and instincts are built around that lifestyle. If the instinct did not support the lifestyle, the strategy would not survive. I suggest the concentration of food around Canberra is a strange and recent situation, encouraging adults to hang around. But this is not what they are adapted to. My best guess (or I think the simplest concept to fill in the bits we don’t know, consistent with what is known) from this is that young cuckoos learn absolutely nothing from their parents. Mainly because they normally never have the opportunity to see them. This is not just because of being parasitic but surely being parasitic makes it almost certain that it is the case. There are many other groups of birds that have brood parasites among them (cowbirds, at least one duck, the whydahs which are finches). I certainly don’t agree with your “unlike all other birds,”.  There are many other birds for which the chicks have little or no involvement with their parents. I mentioned mound builders. Domestic chickens, turkeys, ducks, etc are hatched by machines and yet grow up to be marginally normal if given a chance. For most sea birds, parents take great care feeding the chicks (from which there is not much to learn), until the chicks fledge, but then when the dangers are greatest and there is the most to learn, the chicks leave the nest, the parents are long gone and have nil further involvement.


For cuckoos, I suggest they cannot possibly know (through learning) who their real parents are and it appears unlikely that father cuckoos can have any knowledge of who their kids are (mothers maybe). The idea that male Koels would escort their kids on migration might sound all very lovely to us and may match a situation in those birds where there is a very tight family bond when they know exactly who they are. Maybe birds like storks and geese. The idea that it would occur for a parasite is to me just too weird. Why would a male Koel be so devoted to a kid it doesn’t know is his kid? Also as far as I know, cuckoos do not ever migrate in company of family, always solitary. So I see no real evidence that would provide any suggestion that such (weird) guidance occurs. Yes maybe someone can find an exception (I have hinted at Channel-billed Cuckoos).


I accept that you “feel that , on balance, it was wiser and more thoughtful of Wildcare to choose to release the juvenile where there were other Koels.” Although more to the point, I would say, where the presence of other Koels suggests a supply of suitable food. Yet I would have been really surprised if both young Koels would tolerate each other and remain together until it was time to migrate and even more weird if there was any kind of cooperation between them. Indeed you inform us that you did not see both together after that release. No surprise to me.


It is also a bit strange to me as to why Wildcare get to have a baby Koel. I don’t know the story but I have my suspicions that someone might pick up an early leaving fledgling Koel, thinking, probably quite wrongly, especially as they might not know what it is, that it is abandoned. It had already done its damage and almost certainly still had its foster parents there available to do all the hard work………




From: John Harris [m("","jwharris");">]
Sent: Sunday, 1 March, 2020 2:25 PM
To: Philip Veerman; 'Canberra Birds'
Subject: Re: [canberrabirds] End of the Koel Saga


I think that Wildcare were doing the very best they could with the information available. Yes, of course, there was food in my backyard  as opposed to some arbitraryrandom piece of  drought-affected bushland. I think it also reasonable to release the juvenile where it could interact with other Koels.  I think it more reasonable to presume that the young Koels need to learn something from the adult Koels than to speculate that they learn nothing. That is to suggest that absolutely everyaspect  Koel behaviour is imprinted in their genes, up to and including the migration and even up to and including knowing that they are Koels at all, knowing that they should interact with other Koels. I know that it is theoretically possible that 100% of Koel behaviour is instinctual but I doubt it. Just because they are parasitic, does that mean that unlike all other birds, they have nothing to learn from observing adult behaviour?

I feel that , on balance, it was wiser and more thoughtful of Wildcare to choose to release the juvenile where there were other Koels.




From: Philip Veerman <>
Date: Saturday, 29 February 2020 at 6:56 pm
To: John Harris <
>, chatline <m("","canberrabirds");">>
Subject: RE: [canberrabirds] End of the Koel Saga


Hi John,


Sure interesting ideas and also Jack Holland’s input is very useful. I will add some ideas to both. There are occasional observations of parasitic cuckoos of various species feeding fledgling cuckoos of their own species. Even though the parasitic habit is complex, maybe they still retain some of the basic instinct of a bird to stuff food into a big bright mouth, just enough to show the behaviour occasionally. Although that is when the birds are still very young and not ready to migrate.  Some cuckoos are not parasitic, so the child raising instinct is in there somewhere not all that far back in history. It is no surprise that the Red Wattlebird pair continue aggression towards the adult Koels. It is one of the weird things that they recognise adults as a threat and yet still tend to fledged young that look by then really quite similar. In the meantime in your story it would be easy that the adult Koel would be attracted to the same food source as the young bird was. Is there any meaningful interaction between the adult Koel and the young one? Hard to know. For me right now, I doubt it. There could be mutual curiosity: “What the hell is that!?” Maybe I should make some noise. That is the thought if any, that I would expect, even if anthropomorphic. By analogy, in mound building birds where the parents display great devotion to the mound, they have absolutely no recognition of any chick that emerges, they are just kicked out of the way. I would be surprised if the adult Koel has any role in guiding the migration of the young one. I am willing to be surprised. In most migrating birds young don’t follow parents in particular, though there will of course be many that do. Apart from those that clearly do fly together, proving it either way is difficult. In the Channel-billed Cuckoo they sometimes migrate as flocks but for other cuckoos has anyone ever seen them migrating as family groups? I have not ever and suspect if so that it would be odd.


As for imprinting, that is maybe the wrong word or if we use the word, it is a special different case. If cuckoos get imprinted in the way other birds do, then they would direct their sexual behaviour towards their hosts, which clearly would be a mistake. However can it be that they get imprinted on the species that raised them to prefer them as hosts when they breed? That would appear to me to be likely. This is why I raised the issue of the Regent Honeyeater host of the Pallid Cuckoo a few weeks back, as I was concerned this could be a problem, but the response I got was that this was a rare event.


About imprinting, it depends if there is any learned component in the vocalisation of these birds. On what possible basis would the baby Koel know to imprint on an adult Koel, which for the most part will not be present (having long gone) but in rare cases such as yours where there happens to be a nice plum tree, will be there. That makes no sense to me. That it clearly does not occur in any other cuckoo that stops calling before then, as jack mentioned, makes me think it is even less likely. The situation (lots of fruit trees to keep the birds nearby) in Canberra is also surely unusual and recent.


The gesture of Wildcare  released the juvenile Koel at my place sounds nice as a thing to do. Has this been done before? Is there more evidence about what happens? I am curious. Did it have any practical value as distinct from releasing anywhere else where it could get a feed? I very much doubt that it had any real benefit to either bird and may I reckon more likely have caused distress to both, by being near each other for a time. Again I am willing to be surprised. I doubt if anyone knows the answers to these questions yet.





From: John Harris [m("","john.harris");">]
Sent: Saturday, 29 February, 2020 4:12 PM
To: Philip Veerman; 'Canberra Birds'
Subject: Re: [canberrabirds] End of the Koel Saga


My recent Koel experience has made me very curious about the possibility of adut Koels mentoring juveniles. I am of course far from the first to observe such an interaction and there are suggestions that adults may be imprinting their call or even preparing to lead the young birds on their northern migration. I should perhaps record exactly what I observed.

When I first reported the commotion in my plum tree, the male Koel was staying so close to the begging juvenile that I was briefly tempted to wonder if he was actually feeding it. After more careful observation over a few days, I saw the Red Wattlebird pair feeding the young Koel. At the same time they kept trying to drive the adult Koel away. That is obviously a very strong instinct in Wattlebirds.

This aggression was the source of the commotion together with curious random birds coming to watch including Currawongs wondering if there was anything to predate.

The Wattlebirds succeeded eventually in driving the male Koel further away although he was reluctant, at first  returning to the plum tree. He eventually gave in and hid himself quietly in a nearby tree. I could always locate him but only because I knew he was there hiding himself. He made no sound.

I saw the juvenile begin to take fruit for itself. The Wattlebirds very soon stopped feeding it although it continued to beg. The Wattlebirds, however, then left and abandoned the young Koel to fend for itself. The male remained nearby and began to call its wirra wirra now that it was no longer wary of revealing its presence and drawing the aggression of the Wattlebirds. The juvenile sometimes roosted in the tree where the adult was and returned to the plum tree. 

It was at about this stage that Wildcare  released the juvenile Koel at my place. For about another 10 days, the male continued to call wirra wirra and I saw a juvenile Koel several times but I do not know which one I was observing becauseI did not see both at once.

I heard the last wirra wirra about a week ago. I presume them to have migrated north although it is also true that the plums have finished.

Are they together?



Rev Dr John Harris,

36 Kangaroo Close,

Nicholls, ACT 2913


P: 61-(0)2-62418472


From: Philip Veerman <m("","pveerman");">>
Sent: Friday, February 28, 2020 9:59:38 PM
To: 'Canberra Birds' <
Subject: RE: [canberrabirds] End of the Koel Saga


It would indeed be interesting to know if adult Koels have a role in guiding or accompanying young birds on their first migration, their own young or even unrelated ones. Given that they have no role in raising them (but it seems they stay in the vicinity), it is a tantalising and curious concept.




From: Denise Kay [m("","denisekay49");">]
Sent: Friday, 28 February, 2020 7:56 PM
To: John Harris
Cc: Canberra Birds
Subject: Re: [canberrabirds] End of the Koel Saga


Wildcare have done a great job as usual , its not an easy job raising a Koel chick 


On 28 Feb 2020, at 4:53 pm, John Harris <> wrote:


The dramatic  saga of the juvenile Koel in my plum tree and the attending male waiting to guide its northward flight has a (sort of) happy ending.

People from Wildcare Queanbeyan read my posts. They had a rescued juvenile Koel which was ready to be released. When they read of ‘my’ juvenile Koel , that there was plenty of food here, and that he had a guide waiting for him, they contacted me and came and released it in my yard.

I cannot honestly say that I saw the released bird after that. I saw and heard a juvenile Koel for about a week after that but do not know which one I was hearing or if it was both. I stopped hearing the juvenile calls about a week ago, only the male wirra wirra.

I have seen or heard nothing for a week now. I presume they are on their journey north. I hope they make it.




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