Male Satin bowerbirds (like the bird pictured here) (Ptilonorhynchus violaceus) build specialised stick structures, called bowers, and they decorate the area around them with blue and yellow objects. Those objects may be natural objects such as feathers, flowers, and fruits, but when close to human habitation they are more often artificial items, mostly plastic. They also paint the insides of their bowers by masticating plant material and wiping the plant-saliva mixture onto the walls, as you see in this photo. Females visit these bowers and based on their inspections choose which male to mate with.