We birded along Yanallpa Creek, the narrowest and smallest creek that we traversed during our Amazon journey, the morning of Thursday, January 19, 2012. We photographed this Saddleback Tamarin, Saguinus fascicollis, that was in the trees of a river-edge forest. Tamarins are squirrel-sized New World monkeys and are closely related to Lion Tamarins. They have claws on all digits except their big toes, and feed on tree gum from preexisting wounds on trees. Living in family groups (typically 3-9 members), only one female will breed. The rest of the group helps rear the young (typically twins). Temperatures were in the low 70's with clear skies and high humidity.