Migration is a type of way from one regain to another from one place to another. However in countries like America, Australia, Canada or New Zealand things can be a bit different. Most countries have people form there own land. Where as some places like those countries are opened form people all over the world to come in permission and live in there.
It all happened in the 17th century when the British colonies come to countries full of low civilized people taking over there land and gun shooting them all. They were weak and there weapons could not defend them so they left to places like the desert. Soon the land became their's with their language and everything. Until over the years they decided to free the low civilized people who are still suffering in the deserts. But they were used to the tropical places now and did not want to go.
In the 19th century gold was found in Australia, America and New Zealand. That was when all the people from all over the world comes over to mine for gold. Raises and conquer over regains started happening because everyone started to concern if the people might take over there landscape. Especially the Asians who were treated with torment and raise. Because they thought especially the Chinese people that they have a lot of manual and afraid that they might take over there city.
Bullies killed many Chinese people and many of them died on the streets. Not only does the government feel careless about this situation but also inspired them to harm the Chinese worse. Until years they had considerations about the Chinese even now some of them still hates the Chinese people.
Now those countries are opened up as a place for everyone from all different nations can exit to there land and depart when they needed to. So that is how the countries have developed over the years. Apart form the second world war which involved many death and victim actions that are raises.