In Caucasia, one motif I've come across is trust. Throughout the novel, Birdie is constantly at war with herself whether to open up to someone and tell them the truth or hold back and hide behind a mask of lies. On pg. 76, Birdie even goes as far as admitting "Lies had become my only comfort." The idea that she had come to associate lying with safety was a direct result of her mother drilling the concept into her head when they were on the run.
At several points throughout the story Birdie is caught in the act; however, she never sees that all of the lying is preventing her from coming to peace and accepting her true identity. She only confuses herself. One example of this from the reading is when Birdie tells the younger children at the beach that she is an Indian Princess. Jim is furious and blames Sheila. "Sheila, I don't know what your child-rearing methods are, but allowing her to lie like she does just isn't good for her. You know that." By this point in the story, Birdie has come to enjoy hiding behind masks of characters she makes up and imagining what she would like her life to be like.
When Shiela opens up and tells the truth of their story to Jim, Birdie is furious. She feels betrayed by her mother and hurt that this man who isn't her father is being brought into her inner circle of truth; however, this creates the possibility in Birdie's head that maybe it would be alright if she opened up and told the truth now too. Finally on pg. 342, Birdie has a revelation and opens up to her long lost friend Ali. "But I kept talking, telling this truth, and it felt unnatural to do it." Her truthfullness is rewarded when Ali's father Ronnie reveals vital information in Birdie's search for her father and Cole.