The White-necked Hawk is a rather small black and white hawk of the Atlantic lowland rainforest in Brazil. It is white overall with black upperparts and black bands both at the base and the tip of the tail. The sympatric Mantled Hawk (Leucopternis polionota) is similar, but is larger, lacks the terminal tail band, and has a dark iris. The White-necked hawk generally perches in the middle strata of tall forest, dropping to the ground to obtain arthropods, reptiles, mammals, birds, and snails. It sometimes follows army ant swarms to feed on fleeing insects. The nest and breeding behavior of this species are undescribed.