What are symbols in A Dolls's House that are associated with Nora?

I have not seen where any of the studies has mentioned this.  One of the biggest symbol is that Ibsen uses the bird and squirrel names Torvald calls Nora in a way to make Torvald look silly and kind.  However, I it is used to such an extent that I feel Ibsen is trying to emphasize that it makes Torvald feel superior.  Therefore giving him control over Nora and she begins to feel helpless and small and unable to take care of herself, actually she even uses it to get what she wants, because she knows that Torvald likes to play the big man.  He also uses this bird to teach Nora to obey:  Helmer. Nora, Nora, and you would be a party to that sort of thing? To have any talk with a man like that, and give him any sort of promise?  And to tell me a lie into the bargain?   Nora. A lie--?   Helmer. Didn't you tell me no one had been here? (Shakes his finger at her.) My little songbird must never do that again. A songbird must have a clean beak to chirp with--no false notes! (Puts his arm round her waist.) That is so, isn't it? Yes, I am sure it is. (Lets her go.) We will say no more about it. (Sits down by the stove.) How warm and snug it is here! (Turns over his papers.)   He is a controlling man and I think that Ibsen wanted to show this.  Torvald only has one friend (maybe) and he has told Nora that Mrs. Linde is a bore, etc, limiting her friends.  He also continually calls her names “featherhead” :  Helmer. What are little people called that are always wasting money? Nora. Spendthrifts--I know. Let us do as you suggest, Torvald, and then I shall have time to think what I am most in want of. That is a very sensible plan, isn't it?

and so forth. She was the perfect wife, because her father was the same type and had trained her to follow the rules. Think as I do, act as I want you to and we will have no problems.