Monk Parakeet

The Monk Parakeet is the only parrot that builds a stick nest, in a tree or on a man-made structure, rather than using a hole in a tree. This gregarious species often breeds colonially, building a single large nest with separate entrances for each pair. In the wild, the colonies can become quite large, with pairs occupying separate "apartments" in nests that can reach the size of a small automobile. Wikipedia