Holden's obsession with where the ducks from the Central Park Lagoon might be a way to distract himself from the loneliness of his life. He doesn't really have any real friends and his constant obsession with the Central Park Lagoon ducks, a question that he can never answer takes up the space in his mind when his usual negative thoughts lie idle. It may be something he returns to when his thoughts run out and he is left with the truth of things.