While phrases about birds (such as the consistent refrain about a mated pair of Mandarin ducks) are very common to the language of nu shu, the manner in which Snow Flower uses the language of birds is decidedly less conventional. For her, both writing about birds and other flying creatures and embroidering them is a way to express her desire for freedom in an acceptable fashion, as her actual freedom is slowly taken from her. Snow Flower is essentially able to use birds as a sort of alter ego for herself, where as a bird she's free and able to soar above the earthly things that keep her subjugated and at the mercy of others. While Snow Flower's fixation on birds and freedom scares Lily as a child, as a young woman Lily repeats these phrases and motifs back to Snow Flower to remind her of her free spirit.
Birds and Flying Quotes in Snow Flower and the Secret Fan
With her bold act, I realized the true purpose of our secret writing. It was not to compose girlish notes to each other or even to introduce us to the women in our husbands' families. It was to give us a voice. Our nu shu was a means for our bound feet to carry us to each other, for our thoughts to fly across the fields as Snow Flower had written.