Clive Woodall
If you enjoyed Watership Down chances are good that you'll like One for Sorrow, Two for Joy, as well.
Set solely among the denizens of Birddom (the world of birds that co-exists with our own), this is an epic tale of politics, romance, and the courage of a young robin named Kirrik. Pretty typically the magpies are evil, the owls are wise and ancient, and the birds in between are all, well, in between.
Enjoyable, if a little tiresome.
Yours