Owl trilogy, book 2: The Lost Domain
Martin Hocke1994

The ancient communities of the Barn Owls and the Tawny Owls are locked in a desperate struggle for territory: a beautiful strech of woodland known as the Lost Domain.

But apart from civil war, there is another, greater danger on the horizon: a Monster Owl is flyng ever closer, killing every living think in its path. Long-time foes must forget their enmity and band together to stop the invader, if they are to save themselves, and the Lost Domain.

This epic tale is told by Yoller, a young and privileged Tawny who is destined to learn a great deal about love and life before the nd of a period in owl history told once before, but quite differently, in The Ancient Solitary Reign