The black-naped monarch or black-naped blue flycatcher (Hypothymis azurea)

The black-naped monarch or black-naped blue flycatcher (Hypothymis azurea) is a slim and agile passerine bird belonging to the family of monarch flycatchers found in southern and south-eastern Asia. They are sexually dimorphic, with the male having a distinctive black patch on the back of the head and a narrow black half collar ("necklace"), while the female is duller with olive brown wings and lacking the black markings on the head. They have a call that is similar to that of the Asian paradise flycatcher, and in tropical forest habitats, pairs may join mixed-species foraging flocks. Populations differ slightly in plumage colour and sizes.