Sociable Weaver
True to its name, the Sociable Weaver (Philetairus socius) lives in groups of several hundred individuals. Together, the birds construct the largest of all bird nests which are used simultaneously by several generations. Even better, nonbreeding birds assist pairs in raising their hatchlings. The impressive nests can reach diameters of 4-5 m and house more than 100 mating pairs! Commonly, the structures are also inhabited by other species, such as the Pygmy Falcon (Polihierax semitorquatus).
The Sociable Weaver feeds mainly on insects and occurs in the desert and semi-desert regions of southern Africa (mostly Namibia and South Africa). I have photographed these birds in the Etosha National Park, Namibia, during a visit in February 2007.
Sociable Weaver
Sociable Weaver
collecting nesting material
Sociable Weaver
peekaboo!
a nesting colony
entrances to the nests
Matt Travels 
That nesting colony is incredible!
yes, these birds are very productive!!