What is "undulated antshrike"

n. a passerine bird of the antbird family, (taxlink Frederickena unduligera species noshow=1).

The undulated antshrike (Frederickena unduliger) is a relatively large species of antbird from the western Amazon in south-eastern Peru, western Brazil, and possibly far south-eastern Colombia. It formerly included the fulvous antshrike, which is found further west, as a subspecies.