Yoshi and Birdo are characters from the "Super Mario Bros." series of video games. Birdo first appears in the North American release of "Super Mario Bros. 2", while Yoshi made his first appearance in "Super Mario World."
Birdo's first appearance was in the game "Yume Kōjō: Doki Doki Panic," which was only released in Japan. Nintendo converted this game to the version of "Super Mario Bros. 2" released in North America and Europe, which is where the character was given the name "Birdo." Birdo appears in this game as a pink anthropomorphic reptile who fires eggs at the player out of its large round mouth. The character was originally described as a male who dresses as a female in the "Super Mario Bros. 2" manual, but Nintendo formally changed the character's gender to female with the release of "Mario Tennis" for the Nintendo 64.
Yoshi is a dinosaur with a frog's tongue that first appears as an assistant to Mario in "Super Mario World." Mario can ride Yoshi as if it were a horse. Yoshi is green in color, but has a number of cousins of different colors who also have special abilities. Designer Shigeru Miyamoto had wanted to incorporate a rideable dinosaur into the series from the first entry, but felt the technology could not handle it until the Super Nintendo Entertainment System was developed.