Tame them by getting their eggs. Use a whip while you're grappled to a flyer. They need five fireplaces to hatch. It doesn't take that long for them to grow, but to hatch them it's thirty minutes. They can be found easily on the white cliffs along with their eggs. I don't care if you like this or not I just wanna give tips.
You can't tame these guys by knocking them out. Instead, you need to steal their fertilised eggs (just like wyverns and rock drakes), hatch them and raise them, just a bit harder than knocking them out. The eggs can, of course, be found in their nests and do be careful while trying to steal one as the Deinonychus is very territorial. Hope this helps :)
The Deinonychus is an agile dino with sharp claws that can pounce and feed on its victim. The Deinonychus can also climb up walls by jumping. This creature is able to climb by jumping from wall to wall. It is very territorial around its nest.