You will need: 1 of any type of wall, 3 oak fences, 2 spruce slab, 1 spruce trapdoor, 1 iron bar, 1 parrot
Step #1: Place you wall were you want your parrot home to be. Then, place you three fences on top of one another like in this photo.
Step #2: Place the spruce slab on the top fence. Next place the spruce trapdoor like in this picture.
Step #3: Put an iron bar under the spruce slab. Then, put a spruce slab one block underneath the iron bar. Finally put you parrot on the spruce slab. That's it!! Here is how it should look like.