Weaver world wonders: The sociable weaver is a common little brown bird in the Kalahari region of southern Africa. Yet this sparrow-sized critter may be one of the most interesting birds in the world! Sociable weavers are unlike most other birds due to their lifestyle and nest building. They weave one nest for their entire colony as well as for future residents.

This is no ordinary nest—it is massive, like a giant apartment block occupied by up to 100 sociable weaver families all year long. Some sociable weaver nests have remained occupied for over 100 years!

From a distance, the sociable weaver nest may resemble a haystack hanging in a tree. But if you crawl under the nest and look up, you can see the entrances to the different chambers within the nest. It's sort of like a bee's honeycomb. Nest entrance tunnels can be up to 10 inches (25 centimeters) long and 3 inches (7 centimeters) wide. Round, cozy nesting chambers are usually 4 to 6 inches (10 to 15 centimeters) in diameter. There may be 5 to 100 nesting chambers in a single sociable weaver nest, providing a home for 10 to 400 birds!

When building the nest, sociable weavers use different materials for different purposes. Large twigs form the roof of the nest and dry grasses create the separate chambers. Sharp spikes of straw protect the entrance tunnels from predators. Nesting chambers are lined from top to bottom with soft plant material, fur, cotton, and fluff. A proper nesting tree has a long, smooth trunk and high branches to discourage slithering predators such as Cape cobras and boomslangs, a type of tree snake.

Other predators include the honey badger and pygmy falcon. For some sociable weavers in Africa, the perfect nest-building tree has become a utility or telephone pole.

Weaver nests need constant care because of the nature of the materials used. Weavers continually add more material to keep the nest intact. The birds may seem like clever artisans with their nest-building ability. But sociable weavers build or add to their nest instinctively—they don't need training and can only create their dwelling place the same way their ancestors have done.