Well, mustelids worked well for rabbits in England. And to be fair, ferrets (they introduced stoats, weasels and ferrets) do spend most of their time in the grasslands preying on rabbits. It's the stoats and weasels that really devastate the birds. The 1080 drops for rodents works on well on mustelids too, as they tend to eat the dead bodies, and 1080 bioaccumulates.

But yeah, in hindsight, thanks guys. But at least they didn't get around to introducing dingoes from Australia to control the possums as proposed.

Their neighbours the Australians brought in the cane toad (Rhinella marina) to control the cane beetle.