Use a thlya when you're around the white cliffs!! They can scale the cliffs, also they can take on these guys when you're looking for eggs, it's easier looking for the eggs on the ground than using a flier. Bonus is that the Deinonychus cannot latch onto a thyla.
I was sitting on a flyer on a cliff above the deinos, thought I was safe to wait for my moment to steal their eggs...had the biggest heart attack when one of them decided to climb up the cliff. I accidentally dismounted in shock and fell right into the packs claws, where they shredded me to death. Don't be scared of them, they smell it.