We didn't use guides because we are very familiar with European birds.
Where to bird - Birding Tourist's Guide to Majorca - www.birdingmajorca.com
Field Guide - Collins - The most Complete Guide to the Birds of Europe - Svensson, Mallarney, Zetterstrom & Grant
Bird Song - order from the NHBS - Bird Songs and Calls of Britain and Europe - Jean C. Roche
Lonely Planet Guide for points of interest.
Make sure you see out Tips and Resources pages - and feel free to contact us for more information.