The theory of island biogeography has influenced strongly on the conservation and management issues of species diversity in the islands. The theory has not limited to islands in the ocean, but expanded to isolated and fragmented areas in the forests and urban. This study has a rare opportunity to explore the species diversity and abundance of birds in the islands of Korea. A total of 151 islands in the west and south areas in the Korean peninsula were examined. The number of species and the area of islands were highly significant (P<0.000) and the number of species and the distance from the mainland showed not so strong relationship. This indicated that bird species diversity has more influenced by the size of the islands not the distance. This can be from the study species of birds that can fly long distance, and also natural characteristics of migratory and resident status. Species-area curve showed that the z-value was 0.21 indicating the area and the bird species are strongly correlated. The long-term monitoring of bird species presence in the islands should be followed for a proper management plan.