Sociable weaver

The sociable weaver (Philetairus socius) is a species of bird in the weaver family that is endemic to southern Africa. It is the only species assigned to the genus Philetairus. It is found in South Africa, Namibia, and Botswana. but their range is centered within the Northern Cape Province of South Africa. They build large compound community nests, a rarity among birds. These nests are perhaps the most spectacular structure built by any bird. The sociable weaver was first described by ornithologist John Latham in 1790. Alternative names include the common social weaver, common social-weaver, and social weaver, Formerly, four sub-species were recognised but the species is now considered monotypic. The sociable weaver is the only extant species in the genus Philetairus. Based on recent DNA-analysis, Philetairus socius belongs to the group of sparrow weavers (subfamily Plocepasserinae) and is most related to the genus Pseudonigrita. These two genera are the sister group of the genus Plocepasser. The most basic genus of the subfamily is Sporopipes. Provided that genera are correct clades, the following tree expresses current insights. Measuring around 14 cm (5.5 in) in length, the sociable weaver has a black chin, black barred flanks and a scalloped back. They weigh 26–32 g (0.92–1.13 oz), and sexes are indistinguishable. The species ranges across northwestern South Africa, southwest Botswana and extending northwards across Namibia. It is strongly associated with the arid savannahs characteristic of the southern Kalahari region. The presence of stiff grasses such as Aristida ciliata and Stipagrostis, an important nesting material is an important determinant of its distribution. The taller grasses and the fire-prone nature of the Northern and Central Kalahari regions may be a factor for the absence of the bird in those regions. The area is semi-arid with low and unpredictable rainfall occurring mostly in the summer. The population has not been quantified but the birds are described as 'common to abundant'. In the southern range of the weaver's habitat, breeding may occur any time of the year and is closely linked to rainfall. In the northern range, discrete breeding season between December to August has been noted. They may skip breeding during years when there is low rainfall and a substantial number (sometimes over half) of birds in the colony may never breed in a given season. Under typical conditions, weavers raise up to four broods per breeding cycle. Sociable weavers are known to assist in the care of younger siblings and unrelated hatchlings and nearly all pairs are assisted by helpers. A mating pair has been recorded as producing nine broods in a single season in response to repeated predation of its young. Unlike northern temperate passerine birds which commence breeding within the first year of life, sociable weavers exhibit delayed onset of breeding, sometimes up to two years of age. Sociable weavers construct permanent nests on trees and other tall objects. These nests are the largest built by any bird, and are large enough to house over a hundred pairs of birds, containing several generations at a time. The nests are highly structured and provide birds with a more advantageous temperature relative to the outside. The central chambers retain heat and are used for nighttime roosting. The outer rooms are used for daytime shade and maintain temperatures of 7–8 °C (45–46 °F) inside while outside temperatures may range from 16–33 °C (61–91 °F).