Wednesday, May 19, 2010

Sociable Weaver Bird

the vast nests of the sociable weaver bird

The Sociable Weaver bird was first described by ornithologist John Latham in 1790.

Measuring around 14 cm (5.6 in) in length, the Sociable Weaver has a black chin, black barred flanks and a scalloped back. The species ranges across northwestern South Africa, southwest Botswana and extending northwards across Namibia.

The sociable weaver is insectivorous. As an adaptation to living in the dry Kalahari Desert, where standing water is scarce, the sociable weaver obtains all of its water from a diet of insects.

The nesting colonies of the Sociable Weaver are amongst the largest bird-created structures. 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 night-time roosting. The outer rooms are used for daytime shade. Sociable weaver nests are used by several other bird species, most commonly the Pygmy Falcon.


The nests can continue to grow sometimes resulting in the branch collapsing under the great weight of the structure.

In the southern range of the weaver's habitat, breeding is triggered by rainfall. 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. A mating pair has been recorded as producing nine broods in a single season in response to repeated predation of its young.

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