I found this article, "The Holy Cross: A real life “Mockingjay” for Catholics" interesting. If you've read the book, the allusion to the mockingjay will make sense:
To me, the idea that ties the religious significance of this story together best is the “mockingjay.” I find in the image of the mockingjay a clear and resounding symbol of the Cross of Jesus Christ. The mockingjay is described as a bird that was first used by the Capitol as a tool of oppression against the districts. It was used to spy on them during the war of rebellion, and thus was intended to be a tool to monger fear, distrust, and docility towards the power of the Capitol...
In the same way, the punishment of crucifixion was authored by the Romans as a tool to oppress the masses by instilling fear in anyone who might have thought of speaking out against them. Crucifixion was a punishment reserved for revolutionists and traitors; those who sought to overthrow Roman authority. In enduring his cross, though, Jesus was able to turn the tables, not only on the Romans, but on the devil himself. What was designed as an instrument of torture and death became, through the power of God, an instrument of salvation for the world. In passively submitting to his violent death, Jesus was able to destroy violence forever. As Christians, we venerate the cross, and display it as a reminder of this reversal, and, like the district citizens wearing the mockingjay, we confidently say that we are no longer susceptible to the snares of death, because of our solidarity with the one who is life itself.
If you've read the books, let me know what you think.