Tangkoko Batuangus Nature Reserve in Northern Sulawesi is probably the most visited wildlife area in Sulawesi – great for birdlife but probably most popular due to its Tarsiers and endangered Crested Black Macaques.
For more details and photographs, please check out my trip report in the blog https://chrishillphotoblog.com/north-sulawesi-trip-report-november-2012/