You’d probably expect that the bird that is responsible for building the largest nests on earth must be a massive winged behemoth, but you’d be wrong. Meet the Sociable Weaver. Their enormous communal nests, constructed of thorny sticks and dry grass in large, indigenous trees or artificial structures like windpumps and utility poles, house up to 500 adults birds and their chicks and are used for generations – some nests are over a 100 years old and weigh over a tonne! The nests provide excellent insulation from the outside weather, never getting colder than 15°C in winter nor warmer than 30°C in summer. These nests are often also utilised and shared by other kinds of birds and animals.
The Sociable Weaver is a small (30g, 14cm) sparrow-like bird endemic to parts of Namibia, Botswana and South Africa’s Free State, Northern Cape and North West Provinces, where they inhabit arid Kalahari savanna and feed on seeds and small insects.
Sociable Weavers don’t breed until after it has rained, which in their distinctly arid range is very unpredictable. While they may not breed at all during severe droughts, in years of good rainfall the monogamous pairs, assisted by chicks from previous broods, may attempt to raise from 4 to as many as 9 clutches of 2-6 chicks each! The youngsters fledge at about 3 weeks old and remain dependent on their parents and their helpers for another 45 days or so after leaving the nest.
As a common species with a stable population, the IUCN considers the Sociable Weaver to be of least concern.