that is true....I am from Scottish blood myself 
I guess what I take is that zoos are certainly not responsible for non-native pests. It seems that the vast majority have been caused by tremendously poor thinking government officials, pet owners, and tourists/ industrial means.
there were also one or two species of widowbirds (whydahs) as well, which have likewise now died outMRJ said:Thinking hard the only others that were escapes that I can think of were spice finches (a possible serious problem) and red bishops(?) - a weaver that managed to populate part of the lower Murray for a few generations, but is now apparently extinct.
One accidentally released native species outside its natural range I have heard about is the Rainbow Lorakeet. They have become quite common in the Shepparton area. I was told by someone who used to have a pet shop in the area that they had a large number escape once, and before that there were no wild ones there.
A media release by Adelaide Zoo about the last beavers:
Zoos SA. Adelaide and Monarto Zoos. Australian Panda home.