The taxi driver who talks with Holden about the ducks is Horwitz. Holden meets him while taking a cab from the Edmont Hotel to Ernie’s nightclub in Greenwich Village, and he asks where the ducks in the Central Park lagoon go when the water freezes.
Horwitz reacts impatiently to the question and redirects the discussion toward the fish, arguing that they face a more difficult situation because they remain in the frozen water. He ultimately says that nature takes care of them. The exchange is brief, but it is one of the novel’s most memorable conversations because Holden repeatedly returns to the ducks as a symbol of uncertainty and change.
Some references spell the character’s name “Horowitz,” but the commonly used spelling in the novel and standard quiz references is “Horwitz.” That spelling variation does not change the character’s identity or make the answer ambiguous. He is not Mr. Spencer, Holden’s former teacher, nor Carl Luce, an older acquaintance Holden later meets at a bar.