Having just replied to a previous post I thought I should mention an App that is a great aid to field identification of birds as well as a huge source of information regarding distribution, breeding, populations, habitat, voice and so on. It is taken from the mighty tome called "The Birds of the Western Palearctic". Normally I much prefer books to screen based media but this is very useful as it is possible to hear songs and calls as well as being a resource readily available for anyone who carries a iPhone or iPad.
Unfortunately a small amount of the birds encountered in Southern Spain (being a guide for Northern Europe) are not featured on the App but I still highly recommend it. I think it costs about €20 which is considerably less than the £160 being asked for the book(S).
I apologise if I'm not supposed to promote things in this way. Here is a web address that will give more information.