Why do birds sing?

Those who study bird vocalisations have distinguished different types of bird sounds, to call and communicate to other birds such things as territorial demarcation, sexual status and availability for mating, alarm, and perhaps other things too such as the discovery of a food source etc... the things you would expect any basic form of communication to express.

But the apparently random and spontaneous songs they sing remain largely a mystery. As charming and joyful as these songs often are, I would suggest that they are actually serving a very particular purpose, and indeed a vital one that is at once more profound, sophisticated, and rich than anyone previously ever imagined.

Whilst sitting in the garden one day I heard the song of the Black bird in a nearby tree. And I began to wonder at the meaning of this song, as many have before.
The first thing I considered is that the Blackbird always sings at the beginning of the day as the sun is coming up, and again at the end of the day, at sunset. Always the first bird to sing, and the last of the day.
Observing it for some time, I noticed that it invariably chooses the most prominent position at the very top of the tallest tree, with a largely unobstructed surrounding view of the local environment. As it sings, it turns it's head with small movements and slight adjustments of posture and position, directing it's song in the various directions for all to hear... What could this mean?

Clearly by taking such a prominent and unobstructed position with the broadest scope, the broadcast of the sound is given maximum range, both to send out the song... but also to hear it return.

Could this be a form of echo-location?

Is the bird actually mapping the environment with song?

We know that sharks, whales and fish in the sea employ such methods to define their environment.
Sharks to locate and sense prey over great distances, fish, to elude them, and whales are known to use the thermal currents as channels for their song to be carried sometimes for miles.

It stands to reason that birds should employ these means also.
Like the marine life mentioned, they are entirely dependent on the fluid environment they live in... in this instance, the air.
Flight requires an accurate and dependable knowledge of the terrain and potential obstacles likely to be encountered in a rapidly changing environment, as birds cut quickly through the air. While evolution has promoted a heightened visual acuity in order to meet this demand in part... it cannot account for the unseen obstacles that may lie in wait behind large structures, or objects appearing suddenly from behind trees and buildings etc. For which the bird, moving rapidly through the air could not have time to compensate for if it were to fly around a corner and encounter this obstacle or obstacles.
I think it must therefore benefit the bird to know in advance just what lies in wait... with the visual sense only employed in a secondary capacity for flight... surely the incredibly slow process of evolution which has modelled the bird for flight, and all the tools required for this manner of life would also have given rise to such an ability.

I think the way this works would be that the song, which is a complex system of tones of various frequencies has different reflective properties at each frequency against different surfaces of differing materials, densities, distances, and shapes, is employed to test the various features of the environment across the frequency range, giving the bird a real sense of the nature of the things it is encountering, their positions... and, most importantly, what may lie beyond them, as sound may bounce off the objects at angles, and travel behind them, before returning.
The continuation of song allows the bird to test the environment repeatedly, so that it can build a picture of those things that are static, and which are moving, and likely to pose an unpredictable problem (cars, other animals etc.).


The Magnificent Bird Brain

All of this builds to a complete language and understanding of sound, through an innate knowledge of the Doppler effect, acoustics, reflectivity and sonic absorbency of materials, and other properties of sound beyond anything humans could conceive of.
The bird being entirely aware of practically everything around it in such a deeply connected way as to almost amount to what we would consider one step short of psychic ability.
Making the much laboured use of the term 'bird brained' entirely redundant, as this level of subtle complexity would amount to one of the wonders of the world.

Returning to the Blackbird, it becomes apparent in light of this theory that by singing at the start of the day, and at the end would effectively be the act of creating a memory of the world around it. It sings at the end of the day to take a sonar snapshot of environment, and again in the morning in order to determine what has changed in the intervening period.


The information super sky-way

Furthermore... each bird would be intimately acquainted with these methods used by other species of bird, as they are founded on the same principles, and employ similar techniques, albeit in different 'dialects' and 'languages'- the pigeon will use it's familiar warbling coo, some birds will click, or trill a song, others offer low frequency hums etc.
This means that each bird not only has it's own ability to test and map the environment in this way to rely on, but use the songs and sounds of all other surrounding birds to assist this mental 'imaging' process, and by listening to their ambient chatter, can acknowledge their positions, orientations and 'see' what they see by recognising the tones they are employing which are suggestive of the materials they are testing. Just what they range of environmental appreciation would therefore be is potentially vast, and as long as they can hear a bird in ear shot they can 'know' what they know about their immediate surroundings.
A very real 'internet' of information conveyed through the air, between an intimately and profoundly interconnected series of life forms more ancient, and effective than our internet could ever hope to achieve!

To test this theory, and investigate it's potential validity, it would be necessary to track birds, and compare their songs in different locations and situations not simply regarding their calls concerning those most basic communicative sounds mentioned earlier (food, mating, territorial concerns etc.) but, as I don't believe anyone has as yet done to my knowledge, in comparison to the shapes, materials, and objects found in one location to another. Where a regular and common object would be found in many separate locations for example, the series of tones used would be similar accounting for proximity to the bird etc.

And finally, if this were the case, the wings of the bird themselves could also serve as an integral part of this function, as well as enabling flight, by acting as 'satellite dishes' which receive and amplify the sound as it flies (look at the Kestrel as it hovers over a field looking for prey... although it can see a tiny movement in the grass, it may be that it uses it's eyes only to zero in on the prey, having first located it by 'hearing it through it's wings'.

So next time you are outside, and hear the songs of birds, have a listen, and wonder... is there more to it than we have hitherto previously thought?

Are these creatures still more incredible than we already thought they were?

...or is it just my imagination?