In "The Catcher in the Rye," what do the ducks mean? Holden had talked about the ducks for quite a few times. What do the ducks mean actually? Are...

Yes, the ducks are important.  For Holden, the ducks represent continuity, something that he needs in his life.  When he goes to Central Park to look for the ducks, he has a question about where they go in the winter.  Technically, what really fascinates him is that they come back in a very reliable way.

Holden is suffering from grief over the death of his brother.  He is isolated from society feeling unable to make a true connection with anyone. Holden finds everyone around him to be phony. 

The ducks in the park comfort him, make him feel safe in the belief that there is something reliable in life.  The ducks always come back, you can depend on it.  This provides Holden with comfort.