Get an argentavis or pteranodon and pump as much health and stamina as you can. Steal a wyvern egg and run as far as you can. The wyverns will catch up and you will die. Now, respawn and grab another flyer and fly back to your corpse. If you are far away enough from the trench, you can grab the egg off your corpse without aggroing any wyverns. If you end up aggroing some because you weren’t far enough, just repeat until you’re far enough to not aggro any. Just be prepared to lose a lot of flyers, so tame a bunch beforehand. As for collecting wyvern milk, see other tips.