Weavers and widowbirds are seed-eaters with robust, conical bills. The name "weaver" derives from their densely woven nests; in some cases these structures are built colonially and may become huge, containing hundreds of pairs. Most weavers have plumages in a combination of black with red or yellow; the widowbirds are mostly black, males having long tails used in display. Besides the weavers and buffalo weavers, other common names for genera within the family include bishops (genus Euplectes), fodies (Foudia), queleas (Quelea) and malimbes (Malimbus). The majority of species are found in sub-Saharan Africa, though some are found in tropical areas of Asia. Red-billed Quelea (Quelea quelea) is an irruptive and agriculturally destructive species, often described as the world's most abundant wild bird.