The Parakeet is a bird that helps players in the Sound application for the Nintendo DSi and Nintendo 3DS respectively. It has also appeared in the Nintendo 3DS Camera application and more recently in Super Mario Maker.
Nintendo DSi Sound
The Parakeet appears on the main menu of the application, and tapping on it in this screen will make it chirp or repeat recorded audio. If you go into the menu for editing or listening to recorded sounds, it will give you some Usage Tips for the software when you tap on it.
Nintendo 3DS Sound
Similar to its appearance in DSi Sound, a Parakeet appears on the touch screen of the main menu, and will chirp and repeat audio. However, there are now a few more Parakeets visible on the top screen. In the SD Card audio menu, a blue-colored Parakeet can appear. The Parakeet still gives usage tips in the editing/listening menu, but now you can go into the settings and view each tip that you received before.
Nintendo 3DS Camera
In this application, the Parakeet now appears on the main screen (Which is also the screen for taking photos/videos) and in the "View Photos/Videos" menu. In both modes, the Parakeet gives you tips when you tap on it. This application also has a menu for reviewing any tips you have received before.
Super Mario Maker
In this game, the Parakeet appears as one of the Sound Effect items that you unlock later in the game. Shaking the item will create a square Parakeet. The normal Parakeet will simply fly down and chirp when activated in game, and the square one does the same, although it makes a coarser "squawk" sound. You can also record a message to play when the item is activated instead of the chirping sound, though this does not seem to work in online levels.