This is the bower of a Satin Bowerbird. The adult male Satin Bowerbird is a rich, dark blue colour, and he likes to collect things which are blue. The bird with the best collection gets the most attention from the ladies. Bowerbirds are one of the few animals known to steal items which are not food from each other. A study was done using numbered pieces of blue glass and the scientists observed the pieces moving from bower to bower as the birds competed for the best collection. It was published in Scientific American.
The Satin Bowerbird is also known to use tools. I observed the bird who built this bower painting it with mud. He mixed some soil with water from an upturned lid in his collection and painted the sticks inside the bower. Other birds have been observed using a piece of bark as a brush to paint with.
By the way - the bower is a display structure, not a nest.