Re: blackbirds and individual variations in singing

["stoatwizard" stoatwizard]

I'd second that

> book called "The Singing Life of Birds" by Donald Kroodsma. 
> Fascinating stories (based on US species, but the principles apply 
> globally) he describes a manual approach based on spectrograms. CD 
> included so you can hear what he is writing about.

and for something based on European birds there is also the Sound 
Approach to birding 

http://www.soundapproach.co.uk

which has two CDs and takes you step by step through spectrograms and 
differentiating some individuals of the same species