Ploceidae, more commonly known as weaver birds or weaver finches, are famous for their nest-making abilities. Each species of weaver bird can be recognized by the type of nest it builds. While some weaver bird nests are highly elaborate structures, others are relatively unsophisticated, and the widow weaver builds no nest at all.
Most weaver bird nests can be found in the branches of sturdy trees in Africa, Western Asia or Europe, all native homelands to various species of weaver bird. There will often be more than one nest in a tree, as weaver birds tend to live in flocks. Although they will build their nests from materials local to their nesting area, most weaver bird nests are constructed from flexible materials, such as blades of grass, so the birds can manipulate the materials more easily. Weaver birds that create more complex nests will actually weave these grasses in an over-under pattern, creating snug, weatherproof nests.
Rather than the bowl-shaped nests created by some songbirds, such as robins, weaver bird nests are shaped more like a cone or an urn with a hole used as both entrance and exit. Some species of weaver bird, such as the white-browed sparrow weaver of Africa, build two nests, one for breeding and the other for roosting. Breeding nests have only one hole while roosting nests have two.
The specific shape of the weaver bird nest depends on the species of the weaver. Unlike the tightly spiraled nests of the sparrow weaver, the buffalo weaver, another type of African weaver, builds large, loose nests designed to house two or more pairs of birds. Like their buffalo weaver neighbors, sociable weavers build large nests to house multiple families, but their nests can house hundreds of breeding pairs. Sociable weavers build the largest nests of any bird on the planet. Consisting of inner and outer chambers, their nests will often sprawl among multiple tree branches. Sociable weavers build permanent nests and because of their use of dried grasses, their nests are susceptible to fire.
No matter the species of weaver bird or the shape of its nest, all weaver bird nests are built by males. While the building behavior is instinctual, the birds seem to learn how to construct stronger nests more efficiently over time. Novice birds have been filmed struggling with the basics, such as tying the first blade of grass to a branch. More accomplished males naturally win more mates.