Cockatiels that are overly excited, cranky, not feeling well, not getting enough sleep at night (10-12 hours of quiet, undisturbed sleep) and grieving birds who have lost a cage mate may also scream. If they do have to be exposed to the sun, make sure to dress them in protective clothing, including sun hats. } Center for Disease, Control, and Prevention. At 4 months old, babies are usually still breastfed, bottle-fed, or a combination of both. Aging cockatiels are prone to various health conditions, including cataracts and renal failure. It's exciting to see them grow in so many ways. Is it wise to let an untamed bird run around. Along with their growing interest in playtime, they may also begin to grow new teeth. {"smallUrl":"https:\/\/www.wikihow.com\/images\/thumb\/8\/8d\/Understand-Cockatiel-Gestures-Step-1-Version-4.jpg\/v4-460px-Understand-Cockatiel-Gestures-Step-1-Version-4.jpg","bigUrl":"\/images\/thumb\/8\/8d\/Understand-Cockatiel-Gestures-Step-1-Version-4.jpg\/aid1657425-v4-728px-Understand-Cockatiel-Gestures-Step-1-Version-4.jpg","smallWidth":460,"smallHeight":345,"bigWidth":728,"bigHeight":546,"licensing":"