In his book Pioneering on the Congo (1900), the Baptist missionary Rev. W. Holman Bentley reveals that this was quite a common phenomenon: 'Sometimes they would find the birds flown - the village empty'.
The reason given was a fear of Arab slave-raids. In reality, it was more often the case that Congolese villagers had fled to avoid being conscripted as porters, and later as rubber collectors, by the Belgian regime.
The razing of villages was another common sight in the Congo Free State. When wild rubber supplies ran low, the regime ordered more rubber trees planted. It was often cheaper to use an existing clearing, like that of a village, than to cut down the forest.