To tame the Nanny bird you need to find a nest(usualy in forested or grassy areas) and distract the parent, DO NOT KILL IT. Once the parent is distracted or unable to get back to you and the nest, hid inside the nest and play a game of Simon says with the baby. It will do 1 of 3 emotes which you must respond to quickly and mimic. After you have successfully tamed the baby it will gain bonus levels