SOCIABLE WEAVER HOME

SOCIABLE WEAVER HOME
A common sight on the road south. These birds live often more than 100 per tree, hence the name. If you get a chance ask Alvina what she thought the nests were.

The nest acts as an insulator against freezing winter nights. As the night air drops dramatically from 63 degrees F to freezing, an occupied chamber in a large nest never falls below 61 degrees.

Despite their dropped-haystack appearance, the structures have a sophisticated architecture, with different materials for different purposes. The birds interlock large twigs to form the strong roof and wedge dry grasses into the insulating bulk of the nest. A breeding pair lines the cup inside its nest chamber with soft grass flowers and other fluffies, and uses green grass to mold a firm ridge at the lip of the cup that will keep eggs from rolling out. The tunnel that leads down from each chamber is armed with sharp spikes of straw that make reaching into a nest a painful experience.

Their nest-building instinct is so strong that when no new chambers are needed, they will fill in a perfectly usable chamber and build a new one below it. The largest nests extend well over 20 feet from side to side and several feet high, containing more than 100 individual chambers. Sometimes, the weight of the giant nests breaks branches and even knocks down entire trees.

The birds use cooperative breeding, when an individual other than mom or dad helps to incubate eggs and feed chicks. Weavers will frequently build a nest chamber to be used by others. Non-siblings will help a breeding pair despite a surplus of nesting space where they could raise their own young. If one pair loses its own brood, the couple may even start providing food for the neighbors' family.

The weavers' primary reptilian enemies are the boomslang and the Cape cobra who could wipe out a colony in one sitting.