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Namibia - Etosha National Park Social Weaver Birds Nest HDR

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 degrees Celsius inside while outside temperatures may range from 16-33 degrees Celsius. Sociable weaver nests are used commensally by several other bird species, most commonly the Pygmy Falcon. Whereas this falcon is mostly believed to be a indifferent in most places, instances of predation of sociable weaver nestlings and animosity with the weavers has been reported from some sites in Kimberley.[8] Red-headed Finches and Rosy-faced Lovebird use the nests for breeding while other bird species such as Pied Barbet, Familiar Chat and Ashy Tit may use it for roosting. Larger birds like owls and vultures use the nest as a platform to build their nests.

 

The entrances to the chambers from below

The nests consist of separate chambers, each of which is occupied by a pair (sometimes with offspring) roost and breed. Nests are built around large and sturdy structures like Acacia trees or sometimes even telephone poles. The trees generally used for nest-building are Acacia erioloba, Boscia albitrunca and Aloe dichotoma. The birds at Etosha National Park also use Colophospermum mopane trees for nesting. Large nesting colonies can be active across several generations, sometimes over a hundred years. The nest appears like a large haystack in the tree. If seen from below, several entrances into the chambers may be seen, giving a honey-comb appearance. The entrances may be about 3 inches wide and can be up to 10 inches long.[9] Sharp sticks may be placed to deter predators from entering. Snakes, especially Cape cobras are the most common nest predators, often consuming all the eggs in all the chambers of a large nest. Nest predation is often as high - in one study 70% of the clutches laid were depredated.

 

Nests built in electricity poles sometimes cause short circuits in the rainy season and can catch fire in the dry season.

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Taken on January 3, 2012