Biggest Bird's Nest

BIGGEST BIRD'S NEST

 The Sociable Weaver or Social Weaver (Philetairus socius) is a species of bird in the Passeridae family endemic to Southern Africa. It is monotypic within the genus Philetairus. It is found in Botswana, Namibia, and South Africa. but their range is centred around Northern Cape Province and southern Namibia. They build large compound community nests, a rarity among birds. These nests are perhaps the most spectacular structure built by any bird. The nesting colonies of the Sociable Weaver are amongst the largest bird-created structures. Sociable weaver’s nests are the biggest nests built by any bird and a single nest can accommodate up to three hundred birds, including their chicks.

 CLOSER LOOK

The nest consists of several chambers, each built by a breeding pair, and it is not uncommon to see the birds busily flying to and from the nests with bits of grass in their beaks adding even more to what looks like a haystack in a tree or on a pole. Often the nest gets so heavy that the branch breaks, sending it tumbling to the ground.

Although it looks like new chambers are randomly added on, the nests are cleverly structured to provide different areas for shelter and roosting. The inner chambers are well insulated, being warmer, and are used for nighttime roosting, whilst the outer ones are used for shade during the day and are much cooler. When outside temperatures rise to uncomfortable levels, the outer chambers can maintain temperatures as low as 7oC.

Sociable Weaver or Social Weaver (Philetairus socius)

The nests face a number of dangers. They can catch fire in summer and, if built on electricity poles, can cause short circuits in rainy weather. Their main predators in trees are Cape Cobras, which have a voracious appetite for the eggs and chicks.  Lizards, insects and honey badgers are also a threat to Sociable weavers. The Pygmy falcon, which cannot survive harsh variations in temperature, uses the weaver’s nest and assists with guarding it from predators.

 

in Etosha National Park, Namibia

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

SOURCE: http://www.wilkinsonsworld.com/tag/biggest-birds-nest/

                   http://en.wikipedia.org/wiki/Sociable_Weaver