Walking in Northumberland by Vivienne Crow
This book gives you a wide variety of walks where wildlife can be seen. Although a walking guide sites like Lindisfarne, Low Newton and Greenlee Lough are all well known birding spots. Areas like the Cheviots and North Pennines have their breeding wading birds and birds of prey while the coast has its fair share of winter migrants and sea bird colonies. You would have to pick and choose when to do a walk if wildlife was your main aim but there is plenty of history around many of the walks with castles, forts, burial sites and even cup and ring stones to look for to keep you interested. Ideal for short and long walks.