Six months ago I set up a bird feeder on the fire escape behind my apartment. I put a small piece of paper next to the kitchen window, where I can spy on them and notate all the different species that have come to visit since. It's given me a chance to observe their olympic-worthy avian gymnastic abilities, which makes them such great weavers.
Birds are the true sculptural masters. They use the wings, beaks, bellies, feet and even their own saliva to build these master pieces. But just like humans, the mastery of weaving doesn't come out of nowhere - they have to learn how to do it. This video is a true gem in showing how weaver birds build their nests. It not only shows the structural logic that is followed in building a nest (there are steps involved that lead from one stage to the next), but it also show the process of learning as the younger birds figure out how to make a nest.