The Mockingbirds are a pair of mutated mockingbirds who disrupted life in the Titan Tower as revenge for Robin's destruction of their nest. They were eventually mutated again into highly intellectual beings and fled the Tower once attacked by Robin.
The Mockingbirds were originally regular birds who took residence in the Titans Tower chimney, inadvertantly creating a blockage which Robin was forced to investigate. Upon discovering their nest, Robin attempted to drive them out but the birds mocked his efforts and brutally beat him after he attempted to force them to leave. They were eventually thwarted after Robin released birdy-cide, a toxic he created to expel the mockingbirds. Their honor lost, the Mockingbirds weakly landed in the bushes where they experienced a mutation which changed their pigment color, granted them muscles, and gifted them the ability to speak English.
They later donned clothes and played music outside the Tower in celebration when the other Titans headed outside to investigate. The Mockingbirds quickly garnered their support with the Blue Mockingbird catching Starfire's eye.