Scale up from Rat Island to the planet and tell me what it implies..... this is a 4 page good read.
Grand Quest to Rid Island of Rats [ABC news]
Centuries ago, Rat Island was believed to be a virtual paradise for seabirds -- a spongy redoubt for tufted puffins, whiskered auklets, and storm petrels. But then came the rats, which turned the fecund habitat into a near-dead zone. Now scientists are trying to return the uninhabited island to its original splendor – an experiment that environments believe could be a model for restoration but some critics say is a waste of money.