What is in a song? – Blue Wren song slowed down
Sep 22nd, 2010 by andrew skeoch

Birdsongs often sound like simple, twittery noises to our ears, but what do birds hear? It is difficult to know of course, but the first thing to notice about birdsong is that is often incredibly complex sonically.
To give you an idea of this, I’ve taken the song of a Superb Fairy Wren. Their song may be described as a loud, brisk, merry reel, often like a tinny alarm clock (from Graham Pizzey’s ‘Field Guide to the Birds of Australia’). It just sounds like a scratchy, ripple of notes – very characteristically a Wren!
You can hear two song phrases on the first part of our sound sample. (Pause when they’ve played – and read on!)
Here is a sonogram of that 3 second burst of song. (A sonogram is like a picture of what you’re hearing, with time (in secs) on the horizontal axis and frequency (kHz) on the vertical.)
Just look at it. You can see that this wren is putting a wealth of sonic acrobatics into his song – far more than we are aware of to just hear it.
(Click on the image to view it larger if you like. By the way, some of the fainter lines below are from background birdsong, Robins and Magpies)
Why don’t we hear this complexity? Probably because we have a different perception of the world around us than a Wren probably does. To get a ‘Wren’s-ear listen’, we can slow the sound down.
How slow? Well, a wren has a possible lifespan of around ten years. They rarely get that old due to high mortality, so that is a potential lifespan. You could say that they live their life in around an eighth the time we do. So I thought; what happens if I slow down their vocalisations by eight times? This would drop it several octaves and bring it more into our human hearing range – and also slow it down to our pace of mental comprehension.
The result is pretty extraordinary, I think you’ll agree. Here is an expanded sonogram of the whole song. Click to expand, and you’ll probably want to play the sound sample again and follow it on the sonogram.
I was amazed to hear what this Wren is actually doing, and how, well, ‘human’ the phrasing is. At this speed, you may may be tempted to actually imitate what this Wren is singing with your own voice. If you try, you’ll realise it is not that easy – there is a lot of sonic subtlety in there.
Indeed – it is comparable with the amount of subtlety that we articulate in our singing and speaking.
Which leads to the question; how much of the acoustic information and variety in a Wren’s song is actually intended? In other words, a part of it’s communication? It is obvious that birds need their songs to survive, and that they respond to them in acutely subtle ways – but how much is conscious for them?
Just to compound the puzzle, consider this.
While each three-second Wren song sounds superficially the same to us, they are actually very different. Here is a sonogram of the second song phrase, and you can see it is different to the first.
They are each comprised of very different sonic patterns. When you make a sonogram of them or slow them down, you can see and hear these different phrases. So Wren songs are like snowflakes – each one unique.
Are we just witnessing the variability of nature, an artefact, a ‘can’t quite do it the same twice’ phenomena? Or is this a vital part of Wren survival? Nature is not usually wasteful, so is all this detail just ‘acoustic junk’, or actually an intentional part of Wren communication?
Instinctively, I lean toward the latter. I reckon it means something to Wrens. It is tempting to imagine that each of their songs is like a human sentence; saying something with a unique meaning. But I feel it is more likely that, if it is intended, then it is more akin to our way of singing a song, where we hear the song as one expression, even though it is comprised of many melodic phrases. It is also likely that it is a marker of individuality and virility; ‘this is my song, and see how varied and fine it is!’
But I am guessing. I am no researcher, and I don’t have answers to my own questions. For me, these observations just highlight how little we know about the amazing lives of even a common garden bird like our Fairy Wrens.
So the next time you are hearing birdsong in your garden or woodland, consider what they may be saying to each other. It may be more than you think.

Established in 1993 by nature sound recordist Andrew Skeoch and photographer Sarah Koschak, Listening Earth offers a range of beautiful nature sound recordings from around the world.
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I bought Favorite Australian Birdsong and like it very much.
I was amazed by the sample sound at the top of this page , that by slowing the recording down one can hear it totally different .
I live in Gawler S.A. am an wondering where else can I
get more of your albums retail locations in Adelaide ?
I Don”t have a credit card as I am a Pensioner . I pay cash and can
pay though my Bank account . I prefer a CD not a MP3 .
I use your recording as a background to help sleep and find it most
useful when played on low volume.
I also play it at other times as a background ambient .
My sole purpose of getting this album was to have no music or talking , as a pure unwinding harmony which it is well done !
Hello John,
Glad to hear you enjoyed the blog post.
Best thing to is email us through our contact form, or to call us – telling us which CDs you are after. We can arrange for a direct deposit of funds as payment. We have really pulled back from selling to shops these days. We have such a wide range of recordings now, and many shops are just not able to stock more than a handful of CDS.
All the best,
Sarah
That’s just amazing blog.
I have notice some difference in bird song with in same species in Iceland, where I live.
I will slower the speed on some of my recordings and make some experiments
How fascinating… thanks for this, I’d not have either known this or had any access to this info without you sharing it. Many thanks, it will add to the richness of the experience when I next listen to birdsong.
Wow, this is beautiful – thank you so much!
One thing that strikes me is how much it resembles a whale song. Part of that is the reverb, obviously, and the pitch (and pitch range!) that you don’t usually hear anywhere else in natural sounds. But quite apart from that, I think they’re also structurally similar, they’re phrased, complex, and unique… hmm! Makes me wonder if anyone has ever tried quickening a whale song to bird pitch to hear what it’d sound like if whales were smaller and airborne.
Great post and really interesting hearing these songs slowed down. FWIW, this book: The Singing Lives of Birds – completely changed how I thought about bird songs.
http://www.amazon.com/Singing-Life-Birds-Listening-Birdsong/dp/0618405682
Basically, almost every species of birds learns and practices very specific songs with absolutely precise musical mannerisms. That is, if they stray from the song the slightest bit, it’s meaningless to the other birds of their species. It’s a very formulaic ‘musical culture’. Not unlike today’s pop music scene perhaps!
Hi Jeff,
Indeed Don’s book is a fascinating read. I had the privilege of meeting Don a few years back and recorded an interview with him – you can download it here.
As to how precise birdsong is, and how much variation there is: Seems in passerines there can be quite a bit of variety within the basic song, but less so in the non-passerines where there calls are not learned but ‘hard-wired’. It makes sense that some of the passerine song variation we hear is just ‘organic variation’, but a lot will be individual improvisation to advertise ’strength of character’ through virtuosity (for want of a better way of describing it).
Andrew
This is fascinating, thank-you! (Particularly for someone with dud high-frequency hearing that means I can’t hear the detail in high-pitched calls, even when I can hear them at all).
My thought and question is – I wonder how much extra info there is in the ultrasonic spectrum that doesn’t get captured with 20-20000 audio gear? Putting it another way, when slowed down you can hear no high frequencies of course, I wonder what higher frequencies are actually there and what it would sound like slowed down then? Could you make up some gear to capture say up to 50,000Hz? It would be an interesting experiment, though I don’t know anything about whether small birds use or can hear ultrasonic frequencies.
@ Julian:
There are two technical issues in making recordings capturing higher frequencies than those normally audible to even an excellent set of human ears:
1. A sound recorder with a high sample rate. Standard CD sample rate is 44.1/sec, so only frequencies up to 22kHz will be recorded. Many modern digital recorders will encode at higher sample rates, upto 96/sec in many cases. So that is not a big deal.
2. A microphone capable of capturing high freq sounds. This is where it gets expensive. A device such as Sennheiser’s MKH 800 will record up to 50kHz, but a single mic will set you back $3000 or so.
All this would be useful for insects and bat sounds, but I doubt any mammal or bird would vocalise that high, as they don’t have the anatomical wherewithall to do it.
Andrew