Bolivian Slaty Antshrike

The Bolivian slaty antshrike is about 14 cm (5.5 in) long and weighs 18 to 20 g (0.63 to 0.71 oz). Members of genus Thamnophilus are largish members of the antbird family; all have stout bills with a hook like those of true shrikes. This species exhibits significant sexual dimorphism. Adult males have a gray forehead and a black crown. Their back is gray with a few black spots and a hidden white patch between their scapulars. Their face is gray. Their wings, scapulars, and wing coverts are black with white spots and edges. Their tail is black with white tips and spots on the feathers. Voice: The Bolivian slaty antshrike's song is "a series starting slowly and speeding up into rattling trill, rises in frequency and intensity, reaching peak near end of trill, then falls off". Its call is "a 'caw' note" of variable length that sometimes becomes a "harsh, downward inflected growl".