Undulated Antshrike

The undulated antshrike (Frederickena unduliger) is a species of bird in subfamily Thamnophilinae of family Thamnophilidae, the "typical antbirds". It is found in Bolivia, Brazil, and Peru. == Taxonomy and systematics == The undulated antshrike was described by the Austrian ornithologist August von Pelzeln in 1868 and given the binomial name Thamnophilus unduliger. The undulated antshrike's taxonomy is unresolved. The South American Classification Committee of the American Ornithological Society, the International Ornithological Committee, and the Clements taxonomy assign it three subspecies, the nominate F. u. unduliger (Pelzeln, 1868), F. u. diversa (Zimmer, JT, 1944), and F. u. pallida (Zimmer, JT, 1944). BirdLife International's Handbook of the Birds of the World (HBW) includes a fourth subspecies, F. u. fulva (Zimmer, JT, 1944) that the other taxonomies recognize as a full species, the fulvous antshrike. == Description == 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…