The word 'Islands' conjures up visions of untrammeled existence, where options are rare and threats fewer still. For animals to whom oceanic islands around the globe are home life means exactly that. The island ecosystem is often so simple it can support only hardy generalists like herbivores. It has no place for highly specialized species such as efficient predators who, if they ever got here, would soon eat themselves out of house and home. And because this enforced simplicity prevents a complex food web from developing, island species bask in a sense of security impossible to find on continental shores.