Ava Bigtree
Ava Bigtree is the protagonist of and the narrator of most of Swamplandia!. She is only thirteen years old and is the youngest member in the Bigtree family. She tells the story of how Swamplandia! collapsed from her own perspective, only not narrating Kiwi’s story after he leaves. Ava is fairly gullible, a usual trait for those of her age, but wants to be a hero for her family and for Swamplandia!. The Bird Man is able to trick her into believing that she will find her sister in the underworld with his help. However, her narrative is greatly enhanced by her very observant commentary on her environment, and through that, the reader can see how she matures through the novel.
Osceola Bigtree
Osceola Bigtree is the middle child in the Bigtree family, Ava’s older and Kiwi’s younger sister. She is the only one out of these characters who does not narrate any part of the book. Osceola is unfortunately characterized by a kind-hearted and passive personality. However, her passivity is temporarily banished when she becomes completely fascinated by ghosts after she reads "The Spiritist's Telegraph", which she salvaged from an abandoned library boat. She forces Ava to try to communicate with their mother, who has passed away, but they fail every time, which makes Osceola start to talk to things she calls her “boyfriends.” Her mad attempts to communicate with the dead cause her to be lead away from the theme park, much to Ava’s worry.
Kiwi Bigtree
Kiwi Bigtree is seventeen years old and is the oldest child of the Bigtree family. He is somewhat of a nerd, partly because he is naturally gifted and also because he is always studying by himself. However, Kiwi has obviously never had a real education, and he has essentially made up everything he has taught himself. He is quite a determined character, but his traits start showing a very important duality as he leaves Swamplandia! and goes to work for The World of Darkness. As a result, he doesn’t fit in when he gets out of his family’s theme park at first. All he’s trying to do is earn money for his family and help support them, but he still can’t related to any of his fellow teenage workers.
The Chief
The Chief is the father of all three kids, Ava, Osceola, and Kiwi. He is clearly the leader of the family, and everyone, even his kids, call him Chief Bigtree. He has absolutely no biological connections to any Native American heritage, yet he has created a private little tribe for his family in Swamplandia!. However, because he has created such a special small world for himself, he cannot bear the idea of leaving Swamplandia!.
The Bird Man
The Bird Man doesn’t have a real name except for his special descriptive name, the Bird Man. He mysteriously appears at the family’s theme park and lures Ava into his power by saying that he has magical powers, very similar to what Osceola is fascinated by. The Bird Man announces to Ava that he can guide her to "the Underworld" to save Osceola.
