How were the men Salva is walking with able to find honey?

After a week their group is joined by another group of Dinkas, and some people from a tribe called the Jar-chol. One day, Salva finds himself walking next to a young Jar-chol man named Buksa. Salva is weak, tired, and hungry and when Buksa breaks off from the group to follow a sound he has heard, Salva follows him. A few moments later they stop in front of a large tree. Buksa tells Salva he has been following a bird, and then points up in the tree where Salva sees a large beehive. Salva runs to tell the others, knowing that tonight there will be a feast.