Atonement
Louis accepts the trumpet from his father but is aware that the method employed to acquire it was wrong. He then takes on his father's debt and gets jobs in order to pay back the shopkeeper the trumpet was stolen from, along with money to cover the cost of damage done to the shop. Louis' father also knowingly risks his life to deliver the money to the shopkeeper he stole from to atone for his theft and "rid [himself] forever of the shame that comes from thievery and wrongdoing."
The importance of perseverance and overcoming a disadvantage
Most of the story centers on Louis and his perseverance. Even with the obstacles he deals with that come from being mute, he does not give up. Rather than simply giving into despair, he looks for ways to communicate and work around his disability. Instead of choosing to give up on Serena when she initially rejects him, he becomes determined to win her heart and does so. He also succeeds when he becomes set on getting money to pay back the shopkeeper. Louis' father also demonstrates the importance of persistence, doing whatever to help Louis find a voice. Sam also aids Louis whenever he is in need, such as when he worked to convince the Head Man at the zoo to let Louis and Serena remain free.
Taking a risk can have positive results
In the story, Louis has had to leave his comfort zone and travel to different cities which can be risky and difficult. This sacrifice was a good move and it allowed him to get closer to paying off the debt. Another major example is Louis' father risking his life to bring the money to the store owner. He was injured but he has redeemed himself and unintentionally raised awareness to the Trumpeter Swan's near extinction.
