The Independent recently posted this story about the eradication of feral cats (Felis catus) from Macquarie Island...and it doesn't sound like things are going very well. The cat removal itself worked great: the last time a cat was seen on the subantarctic island was back in 2000. Problem is, there are now over 100,000 rabbits roaming Macquarie, and there have been similar population explosions among the house mice (Mus musculus) and black rats (Rattus rattus) that live there too. The article calls this "unexpected" but I'm not sure how that could be true - it's an island and they killed off the main predator there. Officials are currently scrambling to put together an eradication program and to find funding to control the rats, mice and rabbits before they destroy any more rare bird habitat.