Baya weavers are very social birds. They forage in flocks upto 600 birds for seeds. They perform complicated maneuvers for foraging or reaching roosting sites. They usually forage between 6 and 6:15 in the morning. They conclude their foraging at 6 in the evening. From 12 to 3pm, flocks roost on nearby vegetation.
They are known to obtain paddy or other grains from harvested fields. They also sometimes damage ripened plants and are considered pests. They also depend on wild grasses along with grains for food and nesting material. They feed on insects and sometimes small animals(like lizards).
For breeding, the males build part of the nest and start courting females. Only after finding a female, a male will finish his nest. A male baya weaver can make more than 500 trips to complete the nest. Males are mostly solely the one who builds the nest however females may modify the interiors. They also use sticky mud or dung to stabilise the nest.
These birds are around the size of sparrows and breeding males have a bright yellow crown, dark brown mask, blackish brown bill, upper parts are dark brown streaked with yellow, with a yellow breast and cream buff below. Females and non-breeding males look a lot like female sparrows.
Here are some pictures of a Baya weaver colony in Thiruvannamalai, Tamil Nadu, India. There are pictures of male, females, juvennile males and chicks. There are also nests in different stages.