Undulated Antshrike

The undulated antshrike is a large dark antbird, 22 to 25 cm (8.7 to 9.8 in) long and weighing 75 to 85 g (2.6 to 3.0 oz). The species exhibits significant sexual dimorphism, though both sexes of all subspecies have a crest, a brown to pale yellow iris, a heavy black bill with a hook at the end like true shrikes, and black legs and feet. Adult males of all three subspecies are mostly black with irregular thin white bars everywhere but the throat. Voice: The song of the undulated antshrike's subspecies F. u. diversa is a "short series of 8-13 directly connected 'wuiw' notes, increasing in strength and pitch". The songs of the other two subspecies are not known well though they apparently differ from that of diversa. What is thought to be a typical call is "a long (e.g. 1 second), nasal, downward-inflected churr" written as "TCHEErrrrl".