The Tickell's Blue Flycatcher (Cyornis tickelliae) is a small passerine bird in the flycatcher family. This is an insectivorous species which breeds in tropical Asia, from the Indian Subcontinent eastwards to Southeast Asia. Its range stretches across all the countries from India to Indonesia. They are blue on the upperparts and the throat and breast are rufous. They are found in dense scrub to forest habitats.
The Tickell's Blue Flycatcher is about 11–12 cm long. It sits upright and forages mainly in the undergrowth. The male has the upperparts dark blue and the throat breast and flanks are orange fading into the buffy white belly. The female is duller blue with a brighter blue brow, shoulder, rump and tail. It hybridizes with the Pale-chinned Flycatcher (Cyornis poliogenys) in the Eastern Ghats of India and these hybrids have sometimes been called the subspecies vernayi. The juvenile is streaked and has a spotted mantle.It is an upright long-tailed flycatcher. The male is a beautiful bird which has bright blue upperparts, a red throat and breast, and the rest of the underparts white.[2]
Females are duller, and the red is reduced in intensity and extent. Juvenile birds have scaly brown upperparts, head and breast, with just the wings and tail being blue. They have sometimes been to feed even after dusk.[3] Apart from flying insects they have been noted to occasionally glean crawling insects.[4]

The widespread species shows regional variations in plumage and size and several of these populations have been designated with subspecies names. The nominate form is found in India, Nepal and Myanmar. The Sri Lankan population is separated as jerdoni (or nesea/mesaea said to be darker[5]) and the population in Thailand and southern Myanmar is named as indochina. Further south is the form sumatrensis (Sumatra Island, Malaysia) and lamprus on Anamba Island.[6][7]
The metallic song of the bird includes a series of clicks followed by five or six notes that end abruptly.[5] The metallic song consists of short clicks followed by five or six notes resembling that of the White-browed Fantail-flycatcher. Alarm calls include churr and clicking notes.[2] It is a wary bird and not always easily observed. It is a forest-loving species which is found in thick cover and shade, and particularly haunts the banks of wooded streams.
They feed mainly by capturing insects in flight but their prey include other insects such as termites and earwigs that may be gleaned or picked from the ground.[9]
The breeding season is April to August (March to June in Sri Lanka). It nests in a hole in a tree or amongst rocks that is lined with fine grass and fibres and lay 3-5 eggs.[10][11][12]