Over time, the birds on the two islands may become more different. Which of the following is most likely to happen to the birds on the dry island?

Use the information below and your knowledge of science to answer questions:  

An explorer finds two islands in the Pacific Ocean with very different terrains and climates. One island is wet and full of plants and fruit, whereas the other is dry and barren except for a few plants that grow edible seeds with very hard shells. Nevertheless, she finds birds on the two islands that have many similar traits.