I base it upon a simple comparison of complexity. A dna has far more components, by entire orders of magnitude, than there are notes in any musical composition I know of. Even the DNA of a bacterium is highly complex, containing at least 3 million units, all aligned in a very precise, meaningful sequence.
Thanks for the simple comparison of complexity. I continue to await your mathematical demonstration which will back up your claims about relative probabilities of birds chirping symphonies and DNA existing. You do realize that "DNA is super complicated" is not a proof of your claim, correct?
Once again: State your assumptions. Show your work. Back up your claim.