The Big Bird takes the form of a massive bird-like creature with large, broad wings, thin, stick-like legs, and a comparatively small tail. She has brown feathers covering almost all of her body with purple plumage on her chest and belly. She has a huge jagged beak that extends to her forehead and is able to hold a large number of objects and has no visible eyes. Her interior is encrusted with gemstones that are encased by bubbles.
While attacking the Crystal Gems at the Sky Spire, she attempts to eat Steven and Steven Jr. Opal critically injures Big Bird by punching through her stomach to retrieve both Steven and Steven Jr., resulting in her reforming into many smaller birds. Big Bird is then defeated by Opal, who shoots her smaller versions with her arrows. Following her defeat, the gems comprising Big Bird are automatically bubbled by Opal.
Avian Physiology: The creature takes on the form of a colossal bird and thus has the same innate abilities a bird has, such as the ability of flight and the use of her talons and beak as weapons.
Super Ingestion: Big Bird consumes people, animals, and objects indiscriminately.
Fission: When she sustains serious damage, she splits into numerous smaller versions of herself, which are simply tiny heads with beaks and wings. This also appears to involve fragmenting her gem.