These days, "extinction" of animals has been very known to all over the world as one of "Environmental problems". It has been appreciated that the actions to protect endangered animals are taken for granted, but how the people can do, who had threatened ecology directly.
There has been a lot of unique and weak animals in island which has been separated from any other continents. This locating situation makes the creatures lack of development. They cannot be stronger than other continential animals, because they had been able to live without some competitions.

Poor dodo, poor giant moa. While they were being hunted and chased by strangers, they must have had nothing to do about it. And, immigranted people must have had no idea, no concern about them. The dodo has been extinct since the mid-to-late 17th century, and the giant moa were also extinct by 1500. In the world, a number of animals have been endangered, and people have been worried about that.