Huntsman Series by Douglas Arthur Hill

They had come - on the first day of the world as it now was. They stalked over the world with cold, alien indifference. They are the Slavers, alien invaders on an embattled Earth. In this brutal world, Finn Ferral is a young huntsman with a dangerous gift - he is wild and instinctive, more wolf or hawk than man. When his father and sister are captured by Slavers, Finn follows - right to the heart of the Slavers' lair...

Finn Ferral travels through the wilderness with his contingent of rebels, ever aware of the Slavers' spywings. But his capture takes him by surprise. He is taken to the Alien Citadel, where his huntsman powers are worthless and where no human stands a chance of survival.

The Wasteland people, fighting to save the Earth, are being driven into the fearsome radioactive Firesands by the relentless advance of the Slavers.As Finn, Baer and the other warriors gather for a last great struggle the arrival of an alien spaceship reveals a new threat, even more deadly than the robot-like aliens.Finn is captures and enslaved within the mighty walls of the alien Citadel, the Slavers' mountain fortress... moreThe Wasteland people, fighting to save the Earth, are being driven into the fearsome radioactive Firesands by the relentless advance of the Slavers.As Finn, Baer and the other warriors gather for a last great struggle the arrival of an alien spaceship reveals a new threat, even more deadly than the robot-like aliens.Finn is captures and enslaved within the mighty walls of the alien Citadel, the Slavers' mountain fortress. Relying on nothing more than his uncanny wilderness instincts, he eventually escapes only to learn the devastating truth about the Slavers and their final plans for Earth and its people. less