A small correction: Jabberjays were the mutts used for surveillance and reconnaissance, mockingjays were what happened when Jabberjays interbred with wild Mockingbirds. Nature reclaiming its beast allowed for the districts use them as a tool for communication, an insult to the capital who was trying to strip power away from the districts, not give them more. This is why the Mockingjay became the symbol of the rebellion.