Dunkelameisenwürger Frederickena unduliger

Magnificent dark antshrike of mature upland rainforest. Has a large head with a crest and strongly hooked bill. Males are slaty gray with fine black barring; females are tawny orange with fine black barring. Larger than most other antshrikes and antbirds in its range. Forages singly or in pairs in open understory, and seems to be somewhat rare throughout its range. Its song is a gradually rising series of low whistles given at a steady pace.