You don’t have to steal these guys eggs, they’re a passive tame and eat crystal. If you go to the desert area and find them they cannot be passive tamed though. You can find the ember wyverns around the volcano which is in the middle, tropical wyverns can be found bottom left of the map, the blood wyverns are to the right of the tropical wyverns and above the desert, they have a smaller area so look for red crystals. These guys are not aggressive (unless you go to the desert I think think) so the only difficult part is finding them and following them. Make sure to be on a flyer