The Birdmen were a species of avian humanoids who possessed the power of invisibility. Led by a Queen, they had intended to conquer Earth, but first scouted the Dalek homeworld of Skaro as a testing ground to launch their invasion. Ultimately, however, the Daleks' sensors detected the Birdmen despite their invisibility, and the invaders were exterminated. (COMIC: The Invisible Invaders)