Apparently there are up to 56 different species that have established themselves and are breeding. 

The Monk and Red-Crested Amazon are the most prevalent, along with the Nanday Parakeet. Take precautions so that your pet Bird does not join this group.Birds should not be out of the cage if doors or windows are open or opened frequetnly. Use a flight leash and/or carrier when taking your pets outside for any reason.

There is an article here where you can read more

Please don't let your Bird become one of these, use a Carrier if you go outside.