Weaver birds (Family: Ploceidae) are medium-sized passerines, about seven to eight inches (18-20 cm) long, and widespread in Asia and Africa.
These species all possess the ability to construct a complex woven nest. Although they may try to eat almost anything, the bill of weavers is typically
robust and tough—ideal for crushing seeds and grains, but also put to ingenious use by the industrious birds.
Weaver birds are the architects of the bird world. Designs and neatness of construction vary widely among the different
species of weaver birds. Some are simple and scruffy, with a small tube and roundish nests. Other species build much more elaborate nests, with the strands
of grass carefully interwoven to form a well-defined structure. The main part is a hollow sphere, lined with nesting material, accessed through a long
tube which has a small entrance hole. The nests are usually tough and well-secured so a high wind will not blow them down. The best weaver birds have
the ability to tie dozens of different shaped knots and loops for which they use their feet as well as beaks.
Among most weavers, the male takes sole responsibility for initial building of the nest. The nest is built before the male gets a partner, so he uses
his "love-nest" to entice a female, who is likely to be very fastidious. If his efforts fail and the disinterested female flies off, the male will
try again.
A week without success and he petulantly dismantles the entire edifice and begins again in the same spot, in the hope of better luck. In anticipation
of failure, the male ties the knots loosely because, like Penelope of Ithaca, he may want to undo his laborious construction. If he succeeds, his fussy
partner will see to the interior decoration with grass and other soft materials.
Virtually all weaver birds nest in colonies. Like species' nests, weaver colonies also take different forms. Most species prefer separate nests, with some
space in between. Others are not so fussy and locate their nests on any suitable branch. Yet other weaver bird species nest so closely together that the
individual nests merge together and form large colonies—an avian apartment block. Some are tent-sized, comprised of dozens or even hundreds of merged
individual nests. Whatever the form of the nest, the aim of the weavers efforts is to keep out predators, whether snakes, lizards or larger birds. The Cape
cobra (Naja nivea), in particular, is a specialist predator of weaver bird colonies.
Social weavers (Philetairus socius) build huge nests, the most complex of all avian structures. The birds are sparrow-like in size and appearance. The
individual birds join forces and weave a grass roof in the branches of a tree. They then weave vertical tunnels upward that widen into chambers just under
the roof.
Wherever you go in the parks and reserves with dry bush or savanna, there will be trees festooned with the nests. There are many species of weavers in
Africa, some common and others are rarer. Among these, the best nest-builders are those which build flask-shaped nests. The males have black and yellow plumage
while the females may share their mates colors or have dull yellow plumage. Some species in this genus (Ploceus) are difficult to distinguish.
Weavers abound all over East Africa but there are several especially common species. Most often seen is probably the Sparrow Weaver (Plocepasser mahali)
which has brown and white plumage.
Buffalo weavers are the least accomplished nest makers of the African species. As weavers go, they are large, up to nine inches (23 cm) long. Usually in
small groups, they reside in arid areas. their nests are thorn structures with side entrances facing different directions. Dinemelli's Buffalo Weaver
(Dinemellia dinemelli) is common in dry bush and easily recognized from its black, white and red coloration. The Common Buffalo Weaver (Bubalornis
albirodstris) male is black.
Another buffalo weaver is the Red-billed Quelea (Quelea quelea) is a bird that is unexceptional in many ways. Although it weaves a nest, it is a not a
true weaver bird, like the other buffalo weavers. However, its numbers are mind-boggling. It is the world's most abundant wild bird and has a breeding population
in excess of 1.5 billion. The mortality is huge. Nestlings are heavily preyed upon by birds of prey, scavengers, snakes and lizards and small mammals. Marabou and
shrikes take a large number of young. Yet, these have little impact on the numbers and the quelea causes immense damage to crops. The Guinness Book of Records
cites it as the the world's most destructive bird. Huge flocks darken the sky and indeed quelea's are nicknamed "feathered locusts". Their effects on
crops can be similarly devastating. Many methods are used to control the bird. Along with predators, artificial control kills an estimated billion birds each
year, with no impact on the population, probably because individuals can breed at six months old. They roost in huge colonies. One in
Sudan was estimated to contain thirty million individuals.
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