Juvenile Cuckoo

gramps

gramps

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Just a couple of record shots!

This juvenile Cuckoo has been in the trees at WWT Slimbridge for a little over a week now and is generally at least partially concealed by an abundance of twigs and leaves.
It has been frustrating to get a view of it, not just for me but for the staff and other visitors but I did get a couple of shots off today.
The bird is being fed by its 'foster' parents, a pair of hard-working Reed Warblers who are struggling to fulfil its constant demands for food.
In the first photo the Cuckoo is responding to the arrival of one of the Reed Warblers and opens its mouth to take the insect ... and the Reed Warbler's head!
It's amazing that these little birds don't realise something is amiss and amazing that they don't also lose their heads! :eek:


Cuckoo.jpg




Cuckoo-2.jpg
 
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Is it eating its "feeder" at the end of the story? :confused: :jawdrop:
 
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I knew of the trickery but your takes make me realise
the difference in size… crazy! TFS.
 
Great shots and a very good record of behaviour in difficult circumstances, Gramps.

To get any shot of a cuckoo is good. To get a feeding shot is a bit special.

I agree it seems odd that the 'parent' bird would feed this 'monster' . I assume the gape of the young, any young, is a strong stimulus.

Dave
 
Tringa said:
Great shots and a very good record of behaviour in difficult circumstances, Gramps.

To get any shot of a cuckoo is good. To get a feeding shot is a bit special.

I agree it seems odd that the 'parent' bird would feed this 'monster' . I assume the gape of the young, any young, is a strong stimulus.

Dave
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The gape certainly stimulates the feeding but the Cuckoo also calls like young Warblers, not like a normal Cuckoo call so it is well prepared for the deception. :)
 
gramps said:
also calls like young Warblers, not like a normal Cuckoo call
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That too? Crazier! :jawdrop:

…and how will it find a mate later?
 
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Excellent capture,Roger.

Kodiak Qc said:
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Is it eating its "feeder" at the end of the story? :confused: :jawdrop:
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Lol. No,Daniel.

The females grow up to lay their eggs in the nests of other birds and the cycle of this parasitic activity continues. Of the 136 cuckoo species 56 do this and so far 100 species of birds have been identified as 'hosts' .I'm baffled as to why Nature has things this way. There's always a reason for certain behaviour and in basic, simple terms I wouldn't have thought that 'idleness' alone was the motivating factor. In humans idleness isn't in the DNA and I assume it's the same throughout Nature. I've Googled the question in many ways and there's no answer forthcoming,infact that question isn't even addressed, so it's just taken as 'fact'
 
Yes, great find and timing. I've never seen the size difference caught so dramatically. Would be worthy of Springwatch if it was a video. :)
 
guess&press said:
Yes, great find and timing. I've never seen the size difference caught so dramatically. Would be worthy of Springwatch if it was a video. :)
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The size difference is considerable isn't it ... one visitor who spotted it thought it was a Sparrowhawk at first. :)
 
Wow, the size discrepancy is quite amazing. Great work for capturing this interaction!

JohnC6 said:
The females grow up to lay their eggs in the nests of other birds and the cycle of this parasitic activity continues. Of the 136 cuckoo species 56 do this and so far 100 species of birds have been identified as 'hosts' .I'm baffled as to why Nature has things this way. There's always a reason for certain behaviour and in basic, simple terms I wouldn't have thought that 'idleness' alone was the motivating factor. In humans idleness isn't in the DNA and I assume it's the same throughout Nature. I've Googled the question in many ways and there's no answer forthcoming,infact that question isn't even addressed, so it's just taken as 'fact'
Click to expand...
Providing food for young is a very labour-intensive process, and being able to offload that labour on to another animal—in this case, from a different species!—is going to put the parasitic animal at an advantage, as without the burden of having to feed and raise offspring, it can go out to mate and reproduce again. Anything that provides an individual with a reproductive advantage over its peers will end up spreading throughout the population as those with the advantageous trait will have more offspring than those without it. There doesn't need to be a "reason" for it; all that's needed is a difference in reproductive success between those who have a trait or behaviour, and those who don't, and natural selection will do the rest.
 
i_alarmed_alien said:
Wow, the size discrepancy is quite amazing. Great work for capturing this interaction!
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Thanks, it is remarkable isn't it.

i_alarmed_alien said:
Providing food for young is a very labour-intensive process, and being able to offload that labour on to another animal—in this case, from a different species!—is going to put the parasitic animal at an advantage, as without the burden of having to feed and raise offspring, it can go out to mate and reproduce again. Anything that provides an individual with a reproductive advantage over its peers will end up spreading throughout the population as those with the advantageous trait will have more offspring than those without it. There doesn't need to be a "reason" for it; all that's needed is a difference in reproductive success between those who have a trait or behaviour, and those who don't, and natural selection will do the rest.
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Interesting thoughts, however the Cuckoo is at 'Red' status (globally endangered), whereas the Reed Warbler is at 'Green' status (essentially doing well). :)
 
gramps said:
Interesting thoughts, however the Cuckoo is at 'Red' status (globally endangered), whereas the Reed Warbler is at 'Green' status (essentially doing well). :)
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Differential reproductive success explains why a behaviour or trait may spread through a population. The success of the whole species is affected by many factors—availability of food and water, availability of nesting sites, predation, competitor species, weather, life cycle, persecution/protection by humans, and many more—and it does not necessarily follow that a species with a parasitic lifestyle will be more successful than the species that they are parasitic upon (it'd be bad news for the parasite if they were, as they would outnumber their hosts!). It should also be noted that the common cuckoo is at red status in the UK, but globally the species is classified as being of 'Least concern' by the IUCN.

I'd hazard a guess that cuckoos are red-listed in the UK due to habitat loss and the huge drop in insect populations over the past 25 years due to pesticide use, which has had a knock-on effect on insectivorous birds. :(
 
i_alarmed_alien said:
Wow, the size discrepancy is quite amazing. Great work for capturing this interaction!


Providing food for young is a very labour-intensive process, and being able to offload that labour on to another animal—in this case, from a different species!—is going to put the parasitic animal at an advantage, as without the burden of having to feed and raise offspring, it can go out to mate and reproduce again. Anything that provides an individual with a reproductive advantage over its peers will end up spreading throughout the population as those with the advantageous trait will have more offspring than those without it. There doesn't need to be a "reason" for it; all that's needed is a difference in reproductive success between those who have a trait or behaviour, and those who don't, and natural selection will do the rest.
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Thanks for your comprehensive reply. Re 'a reason' ..maybe I should have used a different word but you've explained ' the reason'..the advantages gained. Whilst googling I discovered that the coot does the same but drops her eggs into another coot's nest if she has too many. An experiment shows that coots can count too. An amazing discovery.

http://www1.ucsc.edu/currents/02-03/04-07/coots.html
 
i_alarmed_alien said:
Differential reproductive success explains why a behaviour or trait may spread through a population. The success of the whole species is affected by many factors—availability of food and water, availability of nesting sites, predation, competitor species, weather, life cycle, persecution/protection by humans, and many more—and it does not necessarily follow that a species with a parasitic lifestyle will be more successful than the species that they are parasitic upon (it'd be bad news for the parasite if they were, as they would outnumber their hosts!). It should also be noted that the common cuckoo is at red status in the UK, but globally the species is classified as being of 'Least concern' by the IUCN.

I'd hazard a guess that cuckoos are red-listed in the UK due to habitat loss and the huge drop in insect populations over the past 25 years due to pesticide use, which has had a knock-on effect on insectivorous birds. :(
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The RSPB does show the Cuckoo as "Globally threatened".
Reed Warblers are also insectivorous ... and watching these 'parents' feed the Cuckoo you would find it hard to believe there was a shortage of insects! :D
Whatever, we need to take far more care of our environment as some of the reduction in species is astonishing ... 90%+!
 
JohnC6 said:
Thanks for your comprehensive reply. Re 'a reason' ..maybe I should have used a different word but you've explained ' the reason'..the advantages gained. Whilst googling I discovered that the coot does the same but drops her eggs into another coot's nest if she has too many. An experiment shows that coots can count too. An amazing discovery.

http://www1.ucsc.edu/currents/02-03/04-07/coots.html
Click to expand...
That's a very interesting article - thanks for sharing the link! It's fascinating to look at the arms race that develops between parasite and host, where an advantage developed by the host is counteracted by developments in the parasite. For example, a host that can distinguish its own eggs from those of others will raise more of its own chicks and that trait will thus become more prevalent. That might drive selection towards parasite eggs that are a better mimic of the host eggs, or towards parasites that move to a different, less discerning host. Of course, we are seeing the "winners" in these races, because poorly-adapted individuals reproduce less and pass on their traits to fewer offspring.
 
great find and witness it mate
 
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