Blue jays weigh between 2.3 and 3.8 ounces and have blue, white, and black feathers. They breathe through their lungs, lay 3 to 6 eggs, and young blue jays are called jays. Blue jays live in the United States, Southern Canada, subways, and parks, migrate seasonally, are warm-blooded omnivores that protect themselves and their young by attacking other birds, and are not endangered.