Somewhat smaller than a sparrow and with a stocky build. The male is deep blue above, sides of head and neck are deep blue, and a prominent white patch runs from centre of throat, through breast to belly. The amount of white on the brow and tail show clinal variation from West to East along the Himalayan foothills, which is sometimes taken to distinguish three races:
The western race from the western Himalayas has a distinctive white supercilium and white bases to the outer tail feathers.
The eastern race from the eastern Himalayas lacks distinct white patches.
Usually singly, though sometimes in mixed hunting parties in the winter. Keeps largely to the low trees and bushes, feeding among the foliage canopy, not venturing much into the open. Constantly jerks up its tail, often accompanied by fluffing of head feathers and trrr note, especially in proximity of nest. Diet is mainly insects.
Distribution
Summer: Common breeding visitor to the western Himalayas, from Jammu and Kashmir and Himachal Pradesh to Uttarakhand, and intergrading within Nepal with the eastern race Ficedula superciliaris aestigma which continues in the eastern Himalayas through Bhutan to Arunachal Pradesh. Breeding between 2000–2700 m, occasionally as low as 1800 and as high as 3200 m. Also in the lower hills of Meghalaya and Nagaland, Khasi and Cachar hills, sometimes considered a third race; winter movements of this population is not known. Habitat: Open, mixed forests of oak, rhododendron, pine, fir, etc., occasionally orchards. Winter: Central India from Delhi south to northern Maharashtra, Goa, northern Maharashtra, and eastward to Andhra Pradesh and Odisha. Wintering populations in the eastern states, possibly from Nepal/Sikkim, are mixed: a good part of this population also have white supercilium and basal tail patches. Also sometimes found as a vagrant in the northern part of Bangladesh.
Nesting
Season: middle of April to early July
Nest: soft structure of fine moss with some strips of bark and fine grass, lined with hair and rootlets, place in holes or clefts in trees, at heights up to seven meters, or in a depression on a steep bank. Readily takes to nest boxes in hill station gardens.
Eggs: 3 to 5, usually 4, olive greenish to dull stone-buff, densely freckled all over with reddish brown, or in another type, mostly around the large end, forming a cap. Average size 16x12.2 mm.
