Madge Undersee, the mayor’s daughter, urgently gives Katniss a gold pin to wear to the Hunger Games as her token. The pin depicts a bird that Katniss comes to recognize as a mockingjay, a species of bird that resulted from a failed Capitol project. The pin, then, is a reminder of the Capitol’s failure, of the possibility of the Capitol's failure, and thus hints at the possibility of rebellion.
Mockingjays repeat patterns of notes they hear, and Rue and Katniss use them to communicate with one another during the Games. However, after Rue’s death, mockingjays come to remind Katniss of what the Games have cost her, and their symbolism lights the fire of the rebellion that will be the subject of the next two books of The Hunger Games trilogy.