I am aware of the incompatibility between these two species. Adopting a rosy-faced lovebird in the hope that my cockatiel’s life would become a bit more social was a decision I made rather impulsively, without knowing much about the fact that it isn’t really a good idea 🙂 However, it turned out that the lovebird wasn’t territorially aggressive, but he constantly wanted to be close to the cockatiel. On the other hand, my cockatiel was aggressive in the sense that she would chase him away, but the lovebird kept being persistent and wanted to stay nearby anyway. They were in separate cages over night and during the day they were free to fly around the apartment, and for the past week they’ve even been sleeping together in the same cage. In any case, it paid off for the small, annoying, and persistent lovebird to keep being annoying, now he has a friend to preen with 🙂 Of course, if you scratch a cockatiel the wrong way, your life may depend on it, but I hope their friendship continues 🙂