This is the field guid that i use on my travels in Europe. It is a very handy book in pocket format & has helped me determine many species of bird in my first encounter with the species.
Collins ISBN 0-00-219210-1
If you are like me & you like walking along the beach, hier is a book you can't do without.
ChroomHelm ISBN 0-7099-3787-3
Wildfowl a book with excelent paintings of Swans, Geese & Ducks of the world.
Helm ISBN 0-7470-2201-1