Absence of evidence is not evidence of absence: Discovery of a large, continuous population of Pan troglodytes schweinfurthii in the Central Uele region of northern DRC

•We present the results of our 2004–2009 chimpanzee survey of the northern DRC, as well as a re-survey in 2012.•The Central Uele and neighboring regions are home to one of the largest remaining continuous population of Eastern chimpanzees.•In the core area of the Gangu Forest, chimpanzee nest encounter rates remained constant between 2005 and 2012.•The chimpanzees are falling under increasing threat from the bushmeat trade.