Louis
Louis is the protagonist and a trumpeter swan was born mute, unable to make a single sound. Initially, he was frightened at how this made him different from all the other swans and distressed at how much he felt he was missing out on. Fortunately, his parents are supportive which helps alleviate that worry and he decided to instead focus on how he will communicate. He is very intelligent and a clever bird, being adept at learning to read and write and demonstrating math skills. He communicates with humans by using chalk and a board which hangs around his neck. He falls in love with a swan named Serena and becomes resolved to grab her attention. After convincing Sam to modify his toes using a razor (which will allow him to properly pay), he becomes renown for his excellent, almost ethereal trumpet playing. He is also able to use the trumpet to communicate with other swans. Louis has a good heart and helps those in need when he can.
Sam Beaver
Sam Beaver meets Louis when he is eleven and when the swan was still a cygnet. He is a kindhearted boy and helps Louis whenever he is able to. He is inquisitive and a great lover of animals of nature and feels at home in the wilderness. He keeps a diary where he writes down various thoughts and observations. Through Sam, Louis has been able to get jobs and learn to read and write. Despite him and Louis being different species, Sam seems to have an easier time understanding Louis and empathizes with him easily.
The cob
"The cob" refers to Louis' father. When he discovers Louis' disability, he is at first devastated and worried for Louis but then becomes supportive to Louis and determined to do anything to help Louis. The cob enjoys being somewhat vain and is the more emotional than his mate. He has a penchant for making long, eloquent speeches and has a flair for the dramatic. He is more than just talk, however. He risks stealing a trumpet for Louis and delivering the money owed to the shopkeeper. He genuinely cares for his mate and cygnets and does his best to protect them.
Serena
Serena is Louis' pretty love interest. During his initial attempts at pursuing her, she paid no notice to him due to their communication barrier at the time and thus rebuffed him. Later on at the zoo, Louis successfully courts her with his trumpet playing and saves her from being pinioned. She becomes his mate.
the Boatman
The Boatman is the man in charge of the Swan Boats. He gives Louis one of his first jobs.
Mr. Lucas
Abe "Lucky" Lucas. He is a shrewd looking man and comes off as sly and a fast-talker. He becomes one of Louis' former bosses.
The pen
Louis' mother. Her personality contrasts with her mate in that she is the more down-to-earth, level headed of the two. She shares her mate's concern for Louis.
Applegate Skinner
A camper at Camp Kookooskoos. He goes out to the lake after being made fun of for his unusual name and nearly drowns until he is saved by Louis.
Mrs. Hammerbotham
A teacher who is initially reluctant and cynical about taking Louis as a student but sees that the swan is a quick learner and agrees to help him learn to read and write.
The Head Man
The man in charge of birds at the zoo. He arranges to allow Louis stay at the Philadelphia Zoo temporarily. He almost gets Serena pinioned but she is saved by Louis and he eventually strikes a deal with Sam and Louis to let her be.
