Weaver birds form the most elaborate nests of any birds. Each species has its own form and technique, to the point where experts can identify a species from the shape of its nest. The male bird weaves the nest and uses it as a form of display to lure a prospective female. Poorly constructed nests fail to impress the female, so the male unravels his construction and begins again. Most species weave nests that have narrow entrances, facing upside down. It is generally accepted that this method discourages predators, which provides a strong incentive to build nests of this type.
The entrance to the nest admits the birds, while curious predators have a lot of tough grass to get through. Even snakes have to maneuver around to get to the entrance.
Weaver birds are social birds who abide by the adage "birds of a feather flock together." They usually group their nests together, often several to a branch. Sometimes these are overhanging water, such as these attached to an acacia branch on a tree growing on the banks of the Mara River, Kenya.