South East Island/Rangatira is the third largest island in the Chatham Islands chain. It covers an area of 218 hectares, rising to 224m high above the western cliffs. It is located 800 kilometres east of New Zealand off the southeast coast of Pitt Island.

Ancient Moriori used to travel to Rangatira to capture muttonbirds. European farmers then ran sheep, goats and cattle on Rangatira until the 1960s when the last of these were removed. Rangatira is now a gazetted nature reserve and has been described as one of the world's premier bird islands. It now accommodates the biggest population of the critically-endangered black robin, and another outstanding feature, the millions of storm petrels, sooty shearwaters and broad-billed prions that roost and breed in the forests.