The emperor fairywren was originally described in the genus Todus and later classified in the genus Todopsis. Alternate names include the blue fairywren, blue wren-warbler, emperor wren, imperial fairywren, imperial wren, and New Guinea blue-wren.
Subspecies
Three subspecies are recognized:
M. c. cyanocephalus - : It is the nominate subspecies, and is found in north-western and northern New Guinea.
M. c. mysorensis - : It was originally described as a separate species in the genus Todopsis. It is found on Biak. It's crown tends to be slightly lighter than that of the nominate subspecies.
M. c. bonapartii - : It was originally described as a separate species in the genus Todopsis. It is found in southern New Guinea and Aru Islands. It is slightly darker than the other two subspecies.
Description
It is the largest fairy-wren. It is long and weighs. Males of the nominate race have light royal blue crowns. The forehead, lores, and the side of the head up till the narrow collar is black. The upper back, along with the scapulars and uppertail-coverts is a deep turquoise-blue, with the lower back being blue-black. The upperwing and the tail are blackish-blue with tinges of blue, and the throats and underparts are a navy blue in color. It has dark brown eyes, black bill, and dark grey-brown legs. Females of the nominate race have a head that looks similar to the male, but have chestnut upperparts, white underparts, deep blue throats, and a black tail with whitish tips. They also have lighter are more mid-brown legs. Juveniles look like females, but have a dusky head, rusty brown upperparts, and entirely white underparts. M. c. mysorensis differs slightly in appearance with its crown being cobalt blue instead of royal blue, and M. c. bonapartii is slightly darker than the nominate race.
Vocalisations
Its songs are a reel that are preceded and followed by sets of 3 notes. This call is frequently given by groups of emperor fairywrens while they are foraging. The contact calls for the bird are "tst-tst-tst-tst”, with the alarm call being “tschik”.
It is found on the island of New Guinea and the Aru Islands. It is found in tropicallowland, forests, wetlands, and degraded former forests. They inhabit dense secondary growth that occurs at the edges of forest, along with forest openings, riversides, roadsides and overgrown gardens. They are not as affected by habitat disturbance and appear to like disturbed habitats like gardens and parks.
Little is known about reproduction in this species, but as juveniles have been recorded from March-December, it probably breeds throughout the year. They are socially monogamous but sexually promiscuous, remaining paired throughout the year. It is a cooperative breeder, having helpers, most frequently former chicks, in pairs or small groups to help raise young. The only observed nest was gourd-shaped with a side entrance, placed off the ground in a bush and containing 4 young. The nest was made out of strips of fern and leaves which were woven together with moss.