Humanoid bird

From Memory Alpha, the free Star Trek reference.

Described as a humanoid bird, this creature was encountered by Christopher Pike while in captivity on Talos IV. (TOS: "The Cage")

The humanoid bird was played by Janos Prohaska (who also played the anthropoid ape in the same episode). The costume was a combination of two earlier creature costumes from the television series The Outer Limits; specifically, the Megasoid from "The Duplicate Man" and the Empyrian from "Second Chance".