Update: read part II here
TL;DR: You are faced with a few thousand hectares of rainforest that you know harbours one or more orangutans that you need to track down. Where, how, and why do you start looking?
About a year ago I was doing a lot of drone related work and was presented with the following problem: Would it be possible to use a drone to fly above the Bornean jungle and search for tagged orangutans?
To understand the motivation behind the question we need some background.