In the excerpt below, who does "they" refer to?
There was a small pool at the end of the river, dammed back by sand and full of white water-lilies and needle-like reeds. Here Sam and Eric were waiting, and Bill. Jack, concealed from the sun, knelt by the pool and opened the two large leaves that he carried. One of them contained white clay, and the other red. By them lay a stick of charcoal brought down from the fire.
Jack explained to Roger as he worked.
'They don't smell me. They see me, I think. Something pink, under the trees.'
He smeared on the clay.