Weaver birds are divided into three categories; sparrow weavers, typical weavers and buffalo weavers. Male birds are generally known to be brightly colored. Weaver birds are the only birds that have the ability to tie knots as they make their nests. The entrance of their nests mostly faces downwards and is narrow to prevent predators from attacking them. They make nests that protect the birds from cold, heat and predators. The materials that they use to make their nests are fine leaf fibers, grass and twigs. The nests vary in size, shape and materials used depending with the type of bird. Weavers have blunt conical bills that help them feed on seeds, fruits supplemented with insects, spiders and snails.