After we made our paper birds in modern art, we gave them paper cages made from recycled ice cream lids.  It was pretty simple thanks to Creature Comfort Blog.  Just slice up 3 strips of construction paper about 1/4 of inch thick and use double sided tape to hold them on the lid.  Then decorate the lid inside and out any ol way you want.  We used ribbon and fancy paper.  The trickiest part was putting in the string to hold the bird.  Eventually I began to use a pipe cleaner but forgot to take a photo.  Anyway, the kids loved them and they look super sweet.