How did the Pacific & other islands get settled?

[kcguy]

As I started typing this response, I wondered if bird migrations were a clue.  Did people see birds consistently flying away in a certain direction and assume land must lie that way?

For me, Australia is a place that's always been fascinating.  It was settled around 50,000 BC (or whenever), and I'm not sure that was an obvious destination for anyone.  (I'd always thought Australia was always an island, but a web search makes me think I may have been wrong.)

As far as surprisingly tardy settlements go, I'm fascinated by Madagascar.  Mozambique was one of the first parts of the world to be discovered by humans, but Madagascar wasn't settled until almost the Anno Domini era, and even weirder, it was settled by people from the East Indies.