The best way to get a wyvern on Ragnarok is with a Griffin. Get a high level one (easier with trap) and take it to the Scar. You can grab the wyvern’s attention and fly high into the air, then nosedive to the Plains. The wyverns will stop following you since the Griffin is so fast, and they will be out of the Scar. Now you can go and choose your egg! After grabbing one I suggest still flying away and using the nosedive, just in case there are still wyverns in the trench.