>> I have often wondered if, for example, there are messages modulating 
>> (encoded on) seemingly repetitive bird songs or within many other 
>> familiar sounds of 'nature' such as the 'chirp' of a cricket...

> There are indeed.  Try here for information on the stingless bee's 'beeps' 
> to inform nest-mates of the distance to forage...

Great references.  Thanks.

I guess, though, beyond simple grunts and nudges, in the general direction 
of food, I'm thinking of a lot greater potential data density.

I'm thinking that if we can send paragraphs in seconds on two carrier notes 
that, combined, sound like a yodel, or on a carrier that sounds to the 
casual listener like white noise, and if we can hide information in pictures 
without noticeably changing them (steganography), that critters *could* be 
saying a great deal more than "chickadee dee dee", "moo", ...or "buzz". 

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