I just noticed this thread. Chiffchaffs regularly singing through September and October is a thing that has always puzzled me over the years, though I admit to being too lazy to read up anything on it.
In answer to Henry's earlier query: - Yes, I have heard singing in S. Europe during the winter, though only once. I was birding earlier this year around one of my regular haunts; - Cartagena city, Murcia, where I generally see scores of Chiffchaffs daily through each winter I have been there over the last 8 years or so. It was 31st January, and a particularly fine and calm morning with lots of passerine activity, conspicuous amongst which were many Chiffchaffs and Meadow Pipits together with a few House Martins. To my surprise one Chiffchaff was in pretty full song already, and I made a mental note that it was surely the earliest I had ever heard one. With only 5 weeks or so to go to early March, my deduction, for what it was worth, was that it was probably just getting in some practise, (though I appreciate this may be too simplistic an explanation, and doesn't contribute anything to explain the autumn singing phenomenon).
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I've always found this interesting and have had my own opinion but that has always been based on supposition and little if any actual proven fact. I suppose initially, ageing the singing bird would be a fair starting point. Not necessarily that easy! Why would a migrant Chiffchaff sing? In some sites they are clearly that yet still sing. I usually note that it's not the prolonged singing of spring, more a burst and often bearing no correlation to the weather. I feel sure there's a definitive answer out there in literature somewhere. BWP would be a starting point I suppose but if I lift mine off the shelf I'll disturb all the dust lying on top! I'd always assumed they were first calendar year birds giving their singing voices a try but that could well be wrong.
Thanks Steve for delving into the archives for this.
I've just re-read all the posts here and agree it's odd that it's mainly Chiffchaffs that sing again at this time of year. Still more questions than answers but it rather puts a doubt in my mind about it being linked to day length. I favour singing to defend feeding territory. It might be built into a Chiffchaff's DNA to sing in autumn to warn off other birds - rather like territorial Robins do throughout winter. Yesterday I watched a Chiffchaff vigorously defending it's patch and wondered then if the energy spent was worth the effort.
Haven't waded through it all to see if there is anything of interest but should make a welcome change from endless minutes devoted to rutting deers yet again!! Was very interesting the first time they did it but now
At the risk of starting s******ing at the back of the classroom, don't gonads have something to do with this? As I understood it, if a bird's gonads were developed then the urge to find a mate would be triggered, hence territorial singing to advertise your presence. After young are raised and other overwhelmng stimuli are no longer present, then until the bird's gonads (calm down at the back) have shrunk then there will be some resumption of song. I'm sure there's more to it than that and maybe that's an outdated theory from biology lessons.
-- Edited by dave broome on Saturday 26th of September 2009 09:50:43 PM
Dave - maybe you should have gone into full Frankie Howerd mode and used the word tittering! Bound to get away with that one on the forum!! As interesting though as your thoughts on developing and shrinking gonads are!...and they definitely got me feeling slightly nostalgic thinking of myself as a spotty-faced, teenager tittering at the back of the classroom during biology lessons!.. but surely if it was just alone either of gonads, equal daylight hours or birds practising their songs then might not all species of birds might be expected to recommence singing?
Back to the subject in hand (schoolboy titter).... I think Pete Berry's comments are of particular interest, as it does seem to be the Chiffchaff that is the main "culprit" when singing recommences in late summer/autumn. I have heard Blackcap in sub-song mode in late summer and early autumn and also at Piethorne the occasional Willow Warblers often has a small burst of half-hearted song towards the end of the breeding season, just before they depart. But why is it the Chiffchaff of all the warblers that is the most noticeable? Is it because they seem to be about in greater numbers and for considerably longer than the other warblers? Maybe this is just part of the genetic make up/natural behaviour of Chiffchaff - pretty much in the same way that Robins start to recommence singing after the breeding season and yet as an example of the complete opposite and for whatever reason Blackbirds don't. Why? Maybe it is something to do with trying to defend a territory (for food?) outside of the breeding season? Robins are thought to defend a winter territory and therefore sing but Blackbirds are considered to be less territorial outside of the breeding season and therefore don't sing. Maybe the Chiffchaff falls into the former category? Then again aren't the few Blackcaps that spend the winter here known to be very aggressive and territorial around feeding tables etc and yet you don't (as far as I am aware) here their song in deepest winter. Don't really know the answers and probably these ideas are just too simplistic and have only clouded the waters even further!.... but just bouncing a few thoughts around.
At the risk of starting s******ing at the back of the classroom, don't gonads have something to do with this? As I understood it, if a bird's gonads were developed then the urge to find a mate would be triggered, hence territorial singing to advertise your presence. After young are raised and other overwhelmng stimuli are no longer present, then until the bird's gonads (calm down at the back) have shrunk then there will be some resumption of song. I'm sure there's more to it than that and maybe that's an outdated theory from biology lessons.
-- Edited by dave broome on Saturday 26th of September 2009 09:50:43 PM
Why is it only Chiffys that sing in autumn?never heard a Willow Warbler or any other migrant in full song this time of year(sometimes get a snatch of sub song with other species).Groppers seem to reel again in July,are these adults or juvs on the move?,as they seem to reel in areas they probably haven't bred.I'm up in Scotland at the moment,still a few Chiffys singing up here.
There was a Reed Warbler in full song at the Wigan Flashes on 05 September, and that's not the only time I've heard this species singing in the autumn.
Why is it only Chiffys that sing in autumn?never heard a Willow Warbler or any other migrant in full song this time of year(sometimes get a snatch of sub song with other species).Groppers seem to reel again in July,are these adults or juvs on the move?,as they seem to reel in areas they probably haven't bred.I'm up in Scotland at the moment,still a few Chiffys singing up here.
There was a bird singing in central Manchester yesterday morning on the banks of the Irwell by the Lowry Hotel. 7:00 in morning, bright but decidedly cool....
Just to further this idea has anyone ever heard Chiffchaffs singing on their wintering grounds in continental Europe/Africa, long after from the equinox? I've heard presumerably continental/scandanavian birds singing in mid-winter in Cornwall even where the daylight hours are much reduced, but often only on a particularly warm, sunny day. The songs were a bit iffy and not classic spring renditions. It could be youngsters just practicing the song throughout to improve for the breeding season or older birds keeping their hand in, so to speak. Henry.
Tony is spot on, it's to do with day length which mirrors that of when they arrive and set up territories in March. Can't remember where I first heard of this, though I've always gone along with it although I've no scientific facts to back it up.
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I like the practising idea - sexual selection is a big driving factor for many oddities in the animal kingdom never mind the birding world i.e. a peacocks tail or a swallows tail (see recent article in Birds mag), so why not in this case?
It takes a lot of energy to grow such a tail, so instead of investing that energy in a tail invest it in a song (esp. the case when considering such a "drab" bird) in order to attract a mate and therefore increase your chances of producing more offspring.
We see many examples too of animals spending large amounts of time and energy learning other skills such as hunting, fighting etc.
So why not extrapolate these two commonly understood ideas into one for the sake of chiffchaffs?
Chiffchaff singing at Waterside Mill, Greenfield, yesterday morning when it was pretty nippy and rather dull - couldn't have been confused about the time of year!
Thanks very much for the ideas and suggestions Bill. I agree that a firm answer to this question will be hard to come by but it is certainly interesting to think about and explore. Chiffchaffs are a particularly conspicuous example through the year with a large array of calls over time and between birds. Will have to get my hands on a copy of that book as I heavily rely on vocalisations as a way of finding and identifying birds during my walks. To be able to sex and age more from calls can be done in some species so why not more with a keen ear and experience? Thanks again Bill. Henry.
I personally am more interested in bird songs/calls/vocalisations (call them what you wish) than I am in plumages etc. I have just finished reading a book published in 2006 -The Sound Approach to Birding by Mark Constantine and the Sound Approach team. This is an absolutely incredible book! It is a really thought provoking and riveting read and challenges a lot of pre-conceptions about bird sounds. They don't profess to have all the answers and the idea is to make us all think (a lot more!) about what we are listening to. The book itself is a fantastic read (I read it almost non-stop) and I haven't even listened to the 2 accompanying CDs yet! The book tries to anaylse by sonograms the shape, structure, pitch/frequency and length of bird songs/calls/vocalisations - they challenge the idea that these might not all be separate entities. They also prove and/or provoke debate (dependent on your viewpoint) that many birds can be both sexed and aged based on their vocalisations! There are fascinating facts/ideas on how birds learn to sing, with something on sub song, which moves onto what they call "plastic" song and also then the fully learned version of song - they call it crystallised.
The book states that "an endless array of passerines were known to sing at as little as six weeks old (Goldcrest and Firecrest even start at four weeks". Haven't really answered the questions posed by Henry and Ian. But vocalisations are undoubtedly a incredibly important aspect of a birds life - skills that have to be learnt and practised - I would hazard a guess that this might be part of the practice? - maybe this years young are the ones that sing through their first winter as they learn and hone their skills? Don't know the answer but if a young Chiffchaff that has been born this summer is hoping to breed next year and having to start to look for and then defend a territtory early next spring/summer then there aren't that many months for it to get "up to speed". Finally, if the best singers/vocalists get the pick of the opposite sex then why wouldn't you want to practice your "chat up lines"!!
The great and exciting thing is that we don't know all the answers and reading this fascinating book will just get the cogs of the brain whirring even faster the next time that we all seriously listened to birds as carefully as we watched them!! The book states that most birders don't spend enough time listening to birds and I am sure they are right!
Hope this is of some help. If anyone wants to borrow my copy of this awesome book they are more than welcome............as long as I get it back!!
Henry I don't know the answer but asked the same question this weekend whilst listening to them calling around Elton. I don't think it's territorial at this time of year however as they are moving around so much. Like you, I would be really interested in an answer to this one. Cheers Ian
As migrants, it struck me this morning that all the singing Chiffchaffs i've often witnessed in autumn here and winter down in the SW, wont be the areas breeding birds. So why would they expend energy and risk predation in holding territory at these times of year? Thanks. Henry.
-- Edited by Henry Cook on Wednesday 16th of September 2009 09:45:24 AM
...and they definitely got me feeling slightly nostalgic thinking of myself as a spotty-faced, teenager tittering at the back of the classroom during biology lessons!.. but surely if it was just alone either of gonads, equal daylight hours or birds practising their songs then might not all species of birds might be expected to recommence singing? 
start to recommence singing after the breeding season and yet as an example of the complete opposite and for whatever reason Blackbirds don't. Why? Maybe it is something to do with trying to defend a territory (for food?
) outside of the breeding season? Robins are thought to defend a winter territory and therefore sing but Blackbirds are considered to be less territorial outside of the breeding season and therefore don't sing. Maybe the Chiffchaff falls into the former category? Then again aren't the few Blackcaps that spend the winter here known to be very aggressive and territorial around feeding tables etc and yet you don't (as far as I am aware) here their song in deepest winter. Don't really know the answers and probably these ideas are just too simplistic and have only clouded the waters even further!.... but just bouncing a few thoughts around. 
The book itself is a fantastic read (I read it almost non-stop) and I haven't even listened to the 2 accompanying CDs yet! The book tries to anaylse by sonograms the shape, structure, pitch/frequency and length of bird songs/calls/vocalisations - they challenge the idea that these might not all be separate entities. They also prove and/or provoke debate (dependent on your viewpoint) that many birds can be both sexed and aged based on their vocalisations! There are fascinating facts/ideas on how birds learn to sing, with something on sub song, which moves onto what they call "plastic" song and also then the fully learned version of song - they call it crystallised. 
then why wouldn't you want to practice your "chat up lines"!!