I once had two budgies and one cockatiel, but recently, one of them died and the budgie is lonely now. His friend was yellow and so is my cockatiel. I felt sorry for him so I decided to try to get him a new friend. I introduced both of them (on the budgie's cage) and the budgie seems friendly and wants to become friends with my cockatiel, but he was another story. The cockatiel is grumpy and wants his personal space, he'd hiss and give a few bites (not anything serious) whenever the budgie comes close. My cockatiel acts friendly towards me, however. Is this normal behavior? My cockatiel is going through his first molt by the way, so could this be the reason he is so aggressive? My budgie isn't doing anything wrong, or not that I know of. Once he knew the cockatiel was uncomfortable around him, he kept his distance and would groom the cockatiel's tail when he isn't looking. It's cute, but I feel very sorry for him. Is there a way for them to be friends? I know I'm supposed to play with the budgie too, but he is more of a 'flock' kind of bird, you know? He prefers his own kind much better.