How is Holden Caulfield an ugly duckling?

Holden Caulfield has an inferiority complex. In Chapter 10, he reveals his poor opinion of his intelligence:
You should see her [Phoebe]. You never saw a little kid so pretty and smart in your whole life. She’s really smart. I mean she’s had all A’s ever since she started school. As a matter of fact, I’m the only dumb one in the family. My brother D.B.’s a writer and all, and my brother Allie, the one that died, that I told you about, was a wizard. I’m the only really dumb one.
Holden thinks he is dumb because he has been expelled from three schools for poor grades and nonconformity. He has been criticized by the teachers and administrators at these school, by some of his fellow students, and by his parents.
For nonconformity the world whips you with its displeasure (Emerson, “Self-Reliance”).
For example, Stradlater, who did not like the descriptive essay Holden wrote for him, says,
“God damn it.” He was sore as hell. He was really furious. “You always do everything backasswards.” He looked at me. “No wonder you’re flunking the hell out of here,” he said. “You don’t do one damn thing the way you’re supposed to. I mean it. Not one damn thing.”
It is rather ironic that Stradlater asks Holden to cheat for him and then says Holden does not do anything the way he is supposed to. That seems to reveal the other boy’s value system, which may represent the majority view.
In the opening chapter, Holden reveals that he was “ostracized” by the entire fencing team because he left all the foils and equipment on the subway. Holden antagonizes others because he is lost in his own thoughts. He thinks his problem is that he is dumb, and he is just as hard on himself as his critics. Yet he is actually at least as intelligent as his brother D.B. and his sister, Phoebe. Holden’s keen intelligence is shown in many ways, including the fact that he is writing an entire novel without even realizing he is a “writer,” as well as the fact that his narrative is filled with precocious insights.
His curiosity about the ducks and where they go in winter shows he is curious about everything, which is a sign of intelligence. Intelligence is hard to conceal. You can see it in small children’s eyes—the way they look around and take in everything with obvious wonder.
In Hans Christian Andersen’s story:
The poor duckling was driven about by every one; even his brothers and sisters were unkind to him, and would say, “Ah, you ugly creature, I wish the cat would get you,” and his mother said she wished he had never been born. The ducks pecked him, the children beat him, and the girl who fed the poultry kicked him with her feet. So at last he ran away, frightening the little birds in the hedge as he flew over the palings.
It is interesting that one of the things in which Holden shows curiosity is the welfare of the ducks in Central Park. Salinger may be hinting at the ugly duckling motif in his story of an unhappy boy who is lost and confused and does not realize he is only trying to find himself.
Hans Christian Andersen was something of an ugly duckling, too. Andersen survived and persisted, and in time he became world-famous. Denmark recognized him as a “national treasure.” His work brought him the love he never received as a child.
Both Holden and the Ugly Duckling have adopted the opinions of themselves that have been expressed by others. Both Holden and the Ugly Duckling criticize themselves and want to die because they are so lonely and unhappy, and also because they have been conditioned to dislike themselves. There is a strong tendency in human nature to dislike and fear others who are different, and those who are hated and feared the most are sometimes those who are in some way gifted.
Did Salinger intentionally pattern his story after Hans Christian Andersen's? More likely, both stories dramatize a truth about life and human nature. Gifted people are often made to suffer rejection and abuse in childhood and adolescence because they are different.