Animal architects: Masked weavers

African Weaver birds are fascinating in their ability to weave nests out of grass and while some of them make large communal nests of grass inside trees, the Masked Weaver makes individual nests that are cleverly woven from grass. These birds and their nest are a common sight here in Johannesburg and male birds are very busy creatures, as they construct a nest, hoping to attract a female who approves of the nest and will use his nest and allow him to mate with her. However, if the nest is not to his liking, he will destroy it and make another, over and over again, until one meets with the his approval and on average, each male builds over twenty nests during a single breeding season. These birds cut a lot of grass for these nests and are also quite destructive towards trees, as they strip the leaves off of the branches surrounding the nest. These nests are fascinating constrictions, especially considering that the bird weaves them using his beak.

A close-up of a rejected nest, showing the bird's weaving technique

Today, I'm going to focus on the nests that didn't make the cut: when a nest is rejected by the male, he pulls out the base, making it unusable.

Another destroyed nest, in the crook of the branch of this small Wild Medlar tree. You can see how the branches have been stripped of leaves to build this nest.

If you look carefully at this picture, there are 3 partially destroyed nests in this tree alone

Why didn't these nests make the cut?
Tomorrow, I'll show pictures of successful nests and what is immediately apparent is that these are perhaps practice nests: successful nests are always suspended from a high tree branch, not woven between the branches of short trees. A hanging nest is not easily accessed by predators such as rats and tree snakes will have a hard time getting into a nest as well. These nests above are just too accessible to predators.