Common tailorbird

Taxonomy and systematics

The scientific name sutorius means "cobbler" rather than "tailor" while Orthotomus means "straight-cutting".

The species was earlier placed in the family Sylviidae but more recent molecular studies place the species within the family Cisticolidae, along with Prinia and Cisticola.

A number of subspecies are recognized within its widespread range in South Asia and Southeast Asia. The nominate race is from the lowlands of Sri Lanka. Race O. s. fernandonis is found in the highlands of Sri Lanka. Neighbouring India has O.s. guzuratus in the peninsula and west to Pakistan while towards the north O. s. patia is found in the Terai of Nepal along the Himalayan foothills until Myanmar. A small population of O. s. patia is also found in the northern Eastern Ghats (Wangasara). The hills of northeastern India have O. s. luteus. In Southeast Asia O. s. inexpectatus and O. s. maculicollis are found in Thailand, Laos and Vietnam, Malaysia, Cambodia and Vietnam. South east China, including the island of Hainan, and Tonkin in Vietnam have O. s. longicauda while O. s. edela is found on Java.

Description

The common tailorbird is a brightly coloured bird, with bright green upperparts and creamy underparts. They range in size from 10 to 14 centimetres (3.9 to 5.5 in) and weigh 6 to 10 grams (0.21 to 0.35 oz). They have short rounded wings, a long tail, strong legs and a sharp bill with curved tip to the upper mandible. They are wren-like with a long upright tail that is often moved around. The crown is rufous and the upperparts are predominantly olive green. The underside is creamy white. The sexes are identical, except that the male has long central tail feathers in the breeding season, although the reliability of sexing data accompanying museum specimens used in determining this sexual dimorphism has been questioned. Young birds are duller. When calling, the dark patches on the sides of the neck become visible. These are due to the dark pigmented and bare skin that are present in both sexes and sometimes give the appearance of a dark gorget.

Behaviour and ecology

Like most warblers, the common tailorbird is insectivorous. The song is a loud cheeup-cheeup-cheeup with variations across the populations. The disyllabic calls are repeated often. Tailorbirds are found singly or in pairs, usually low in the undergrowth or trees, sometimes hopping on the ground. They forage for insects and have been known to feed on a range of beetles and bugs. They are attracted to insects at flowers and are known to favour the inflorescences of mango. They also visit flowers such as those of Bombax, Salmalia for nectar and are sometimes covered in pollen, giving them a golden-headed appearance.

The birds roost alone during the non-breeding season but may roost side-by-side during the breeding season, sometimes with the newly fledged juvenile sandwiched between the adults. The roost sites chosen are thin twigs on trees with cover above them and were often close to human habitation and lights.

Breeding

The breeding season is March to December peaking from June to August in India, coinciding with the wet season. In Sri Lanka the main breeding periods are March to May and August to September, although they can breed throughout the year.

Although the name is derived from their nest construction habit, the nest is not unique and is also found in many Prinia warblers. The nest is a deep cup, lined with soft materials and placed in thick foliage and the leaves holding the nest have the upper surfaces outwards making it difficult to spot. The punctures made on the edge of the leaves are minute and do not cause browning of the leaves, further aiding camouflage. The nest lining of a nest in Sri Lanka that was studied by Casey Wood was found to be lined with lint from Euphorbia, Ceiba pentandra and Bombax malabaricum species. Jerdon wrote that the bird made knots, however no knots are used. Wood classified the processes used by the tailorbird in nest as sewing, rivetting, lacing and matting. In some cases the nest is made from a single large leaf, the margins of which are rivetted together. Sometimes the fibres from one rivet are extended into an adjoining puncture and appearing more like sewing. The stitch is made by piercing two leaves and drawing fibre through them. The fibres fluff out on the outside and in effect they are more like rivets. There are many variations in the nest and some may altogether lack the cradle of leaves. One observer noted that the birds did not utilize cotton that was made available while another observer, Edward Hamilton Aitken, was able to induce them to use artificially supplied cotton. The usual clutch is three eggs.

The incubation period is about 12 days. Both male and female feed the young. Mortality of eggs and chicks is high due to predation by rodents, cats, crow-pheasants, lizards and other predators. The young birds fledge in about 14 days. The female alone incubates according to some sources, while others suggest that both sexes incubate; however, both parents take part in feeding and sanitation. The males are said to feed the incubating female. An unusual case of a pair of tailorbirds adopting chicks in an artificially translocated nest belonging to a different pair has been recorded. Nests are sometimes parasitized by the Plaintive Cuckoo (Cacomantis merulinus).