The chance of a bird, especially one of the smaller species coming back is not big. It still might be possible if the cockatiel sees the others and flies back. Cockatiels are birds which don't really have a homing instinct and fly from tree to tree. If the bird was tame, though, he might come back if he isn't too scared.
it depends on how much trust you two have. I had 2 parakeets when I was younger, they opened the cage door themselves and flew out when no one was looking. for about a week they had always come and stay in top of our backyard gate, until one day. they stopped. who knows. maybe they've passed away or they flew away for good.
My little brother opened the cage door, and they've been outside (in a cage) for less than a week. Only one flew out. Is there any chance?
