The Sulphur bellied warbler (Blyth) it is commonly known as olivaceous leaf-warbler. It is small birds in the warbler family. Commonly found in the Indian subcontinent and south East Asia. It is the small bird commonly seen in the bushes of the NEERI Campus, backyards and in Colonies. It is a resident (non-migratory) breeder in open scrub, grassland and rocky hills.

It is having about 10-11.5 cm in size and 7-9 gm in weight. A small to medium-sized leaf-warbler. Has long bright yellow supercilium (A type of special features found in the heads of birds) from base of bill to above ear-coverts, brightest above eye. Food mostly small insects, especially small beetles including weevils), and larvae, also molluscs Like other leaf-warblers it feeds on insects from small branches and leaves.

Breeding seasons are from End of April to early August, Nest is built entirely by female over 4-10 days with the help of a ball of dry grasses, plant.

The species is found in small groups and has a tendency to forage low in the vegetation sometimes even hopping on the ground. They have a single note cheep call. Not globally threatened. Uncommon or local in Tajikistan and Kazakhstan; common or locally common in Pakistan rare in North West & Central China.