Migration is normal, accept it

Abstract

Annual migrations - such as those of bar-headed geese (Anser indicus), which fly over the Himalayas on yearly trips from Mongolia to India and back again - as well as seed dispersal and animals roaming to find new territories and mates, aren't generally seen as comparable to human-mediated translocations across oceans, such as the deliberate introduction of Asian turtles in Hawaii to be bred for food. If monkeys could arrive in the New World 30 million years after the Atlantic Ocean formed; if sweet potatoes could raft to Polynesia on their own; if seeds from Hawaii's koa tree could find purchase on the island of Reunion, half a world away, then even transoceanic range shifts are perfectly natural. Cats and foxes that were introduced to Australia after European settlement in 1788 have helped to wipe out 22 native mammal species, such as the desert bandicoot (Perameles eremiana) and lesser stick-nest rat (Leporillus apicalis).