Birdo

Birdo is a recurring character in the Mario series. She first appeared in Doki Doki Panic, a Japanese game featuring Birdo as the first boss. After its release in Japan, Nintendo of America remade it, featuring Mario characters, but kept the enemies and bosses the same. This remake was known to be Super Mario Bros. 2.

Birdo later appeared in many Mario spin-offs like Mario Tennis and Mario Golf as well as Mario Kart: Double Dash.

Appearances
For the SNES, Birdo appeared in Super Mario All-Stars as a boss, Wario's Woods as Toad's helper, and Super Mario RPG as a boss.

For the Nintendo 64, Birdo was in Mario Tennis as Yoshi's partner, and Mario Golf as Yoshi's partner again.

Birdo appeared in Super Smash Bros. Melee for the GameCube as a cameo, Mario Superstar Baseball and Super Mario Strikers as Yoshi's teammate, Mario Kart: Double Dash!! as Yoshi's partner, and Mario Party 7 as an unlockable character. Birdo can be unlocked in the game by purchasing her in the Duty-Free Shop.

For the Wii, Birdo was in Mario Party 8, Mario Strikers Charged as Yoshi's teammate, Mario Kart Wii as an unlockable character, and Mario Super Sluggers.

In The Super Mario Bros. Super Show, King Koopa's main weapon usually has Birdo as part of its name.

Gender
Birdo's gender has been fluctuated over the time. According to the North American instruction manual of Super Mario Bros. 2: "Birdo thinks he is a girl and likes to be called Birdetta.". However, later versions of Super Mario Bros. 2 make no mention in either the manual or the video game itself. In Super Smash Bros. Brawl, Birdo's trophy description describes the character as "indeterminate gender", and uses the pronoun "it" rather than gender-specific pronouns such as "he" or "she". However, several other sources refer to her as a girl. The confusion surrounding Birdo's gender has also been addressed in a light-hearted matter, such as when Popple pauses before settling on calling Birdo a "dame" in Mario & Luigi: Superstar Saga. In Super Mario Advance though, the Birdos in that game had female voices. Currently, it is strongly implied that Birdo is female, but it has not been officially confirmed yet.

Trivia
In Mario Kart Wii, a blue Birdo is seen in the audience for some tracks, meaning that Birdo may be a species (like Yoshi) and a name.