An inactive volcano, Mt. Sahendaruman dominates the southern half of Sangihe Island. Its forested crater still resonates with the call of rare birds found nowhere else. Almost the entire global population of four Critically Endangered birds are restricted to a tiny area of habitat of less than 2,000 acres—the Sangihe Whistler, Sangihe White-eye, Cerulean Flycatcher and Sangihe Golden Bulbul. They were only recently rediscovered about 30 years ago after expeditions were undertaken to find them.