Captain Jack Sparrow in the Pirates of the Caribbean franchise got his nickname due to a combination of the creative vision of the filmmakers and symbolic associations with the bird. Here are the main reasons:
1.Johnny Depp's idea. The actor playing the role suggested adding a "bird" nickname to the character to emphasize his originality. Director Gore Verbinski supported this idea, which made the name memorable and colorful.
2.Sparrow symbolism. This bird is associated with agility, love of freedom and cunning, qualities that characterize Jack. Just as a sparrow avoids traps, so the captain skillfully gets out of difficult situations, using intelligence instead of strength. In addition, despite it's modest appearance, the sparrow survives in any conditions, which reflects Jack's resilience.

3.Historical parallels. The character was partially based on the real pirate John Ward, who had the Arabic nickname "Asfour" (sparrow). He, like Jack, combined a love of freedom with adventurism.
4.Contrast and irony. The name "Sparrow" creates a contrast with the image of a powerful pirate, emphasizing his unpredictability. It is also a reference to the comic elements of the character, inspired by cartoons like Pepé Le Pew.
Thus, the nickname "Sparrow" became a key part of the image of Johnny Depp's hero, reflecting the character, lifestyle and even philosophy of the character, who, like a bird, does not recognize borders and always finds a way to freedom.