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. They are sexually dimorphic with males having a distinctive black patch on the back of the head and a narrow black half collar (“necklace”) while the female is duller and lacks the black markings. 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. The adult male Black-naped Monarch is about 16 cm long, and is mainly pale azure blue apart from a whitish lower belly. It has a black nape and a narrow black gorget. The female is duller and lacks the black markings. Her wings and back are grey-brown. There are however several geographically separated breeding populations that differ in the extent and shade of markings. Wikipedia – http://en.wikipedia.org/wiki/Black-naped_Monarch