Bird Wyverns (Japanese 鳥竜種) are a class of monsters introduced in the first generation. They are a small to medium sized class that includes Flying Wyverns with slender bodies that are bipedal. There are two groups, the True Bird Wyverns which have wings and the Raptorial Bird Wyverns which are wingless.

Another, fan-made, subclass includes the Aviors, who are more similar to normal birds than the normal Bird Wyverns.