She is very funny and quackative for a duck and a close friend to Sasha. She almost gets eaten by the wolf, but manages to survive. She is sometimes afraid as seen when she imagines the wolf scaring her, and when she swims across a frozen lake to escape from the hungry wolf.
She appears in this segment, based on Prokovief's symphony. Sonia first appears coming out of some bushes (thus revealing she is not the wolf) and greets Peter, and wants to join him and Sasha on their wolf hunt. She eventually gets curious of Peter's popgun as she pretends to use it to hunt the wolf. Sonia even imagines herself capturing the wolf, but soon runs away in terror because of it scaring her and hides under the snow, to which Sasha angrily calls her a coward. She then accompanies Peter, Sasha, and later Ivan on their wolf hunt. She is later chased by the wolf and gets separated from the rest of the group. When she tries to hide inside a tree from the wolf and is intercepted, she is supposedly eaten, and the gang has a thought about her going to heaven. However, Sasha avenges the mistake by taking on the wolf. At the end of the segment, it is revealed that Sonia is not dead, and she and Sasha go off to see the parade.
She made a few cameos as a guest in the show.
- Sonia is represented in the music by an oboe.