Sea birds of the Rat Island in Alaska infested with rats, face the threat of mass extinction. The island was invaded by rats in mid 1700s, from a Japanese or Russian ship that was grounded nearby. Now other nearby islands are also infested with rats. The birds generally lay the eggs on the ground as there are hardly any trees in the island. Rats find it easy to survive on these eggs. Interestingly, one pair of rats can produce a population of more than 5,000 rats in a year. Puffins, auklets and storm petrels are almost at the risk of extinction. State and federal wildlife biologists are preparing to exterminate the rats by air dropping rat poison from helicopters. If they succeed, it will be the third-largest rat free island in the world.
Here is the map that shows the islands that are infested with rats.