This is the definitive CD of bird noises, and covers all 175 species encountered in the UK. The quality of the recordings is very good, as one would expect from a British Library badged product, and as an aid to aural identification this is a useful resource, with each species separated into discrete tracks. Each track is introduced verbally by a gentleman who sounds like he'd really rather have been doing something else than voice tagging bird noises, but his diction is crystal clear and accentless. It's a 2 CD set, with passerines on one CD, and non-passerines on the other.
Not really one for the dinner party or the individual wanting to relax to the sound of birdsong, but peerless as a reference resource. I find I'm now wandering round my local area and managing to pick out individual species much more clearly.