Animals on distant islands after the Flood?

 Augustine is interesting on how animals got onto islands after the Flood. 

Some may have swam. 

Human beings may have taken some. 

The angels may have taken them, either at God's command or with his permission. 

Some may have arisen spontaneously from the earth as when God made the world, which would make the inclusion of all the animals in the ark typical of the various nations thus presenting a symbol of the Church rather than for the purpose of restoring the whole animal population of the world

(The City of God, book XVI, chapter 7)