Simply put, I'm finding the fight with the Kestral to be a pain in the ass. I had problems with the first boss, but I managed to kill him the 2nd or 3rd time around, while this fight with the Kestral seems unbeatable. If I stand back and block, taking a swipe at it from time to time, I end up getting whittled down to nothing while having done little damage. If I try and just rush it with Blood Fury (or whatever it is called), I end up getting cut to ribbons.
What am I missing here?

There isn't any strategy in this fight.

Make shure you start the fight with full health and bloodrage and the rest is just button mashing combined with a bit of luck. Just attack and jump all over the place until the fight is over.