According to the published research literatures, Hainan has 78% species of birds which same as to Mainland and has 40% species of birds which same as to Taiwan. It shows that Hainan became an island later than Taiwan and its kinship of birds to Mainland being more closer compared to Taiwan. Since Taiwan and Hainan becoming islands, the bird compositions there have developed their own local characteristic. Taiwan has some Palearctic region's birds which cannot be found in Hainan, while Hainan has some oriental region's birds which are not distributed in Taiwan.