Ignorance and the toad

[kenney]

No: HPFGUIDX 85063

Excuse me while I display my most obvious ignorance, where in any of 
the books does it mention a Hogwarts choir? with toads? the leaky 
cauldron's shot by shot comparison to the book announces there is 
indeed such a choir and that it has been long awaited...

I must admit, my personal interests lie in that particular field, and 
I'm ashamed to admit that I have over read such an important portion 
of the series (to myself)

Can any of you enlighten me?