Detailed Instructions: This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
Q: Before the introduction of the brown tree snake, Guam was home to several endemic bird species. Among them were the Guam rail (or ko'ko' bird in Chamorro) and the Guam flycatcher, both common throughout the island. Today the flycatcher is entirely extinct while the Guam rail is extinct in the wild but bred in captivity by the Division of Aquatic and Wildlife Resources. The devastation caused by the snake has been significant over the past several decades. As many as twelve bird species are believed to have been driven to extinction. According to many elders, ko'ko' birds were common in Guam before World War II.
A:
What are the names of the two native birds in Guam before the brown snake intrusion?