So a few days later and Leia has figured out that she gets treats for staying on her cage and perches and no treats at all for launching herself onto my shoulder to chase Kira off. I'm teaching Kira to station by giving her treats when she stays on her cage and perches and she seems to be getting the message. On Monday evening I genuinely feared that my head was going to be in the middle of a psittacine squabble but happily, everyone seems to be a bit calmer now.
I've been working on targetting Leia around the room so she has to fly to touch the stick - it's good exercise, gives her something to think about and she enjoys it. Kira was very interested in what we were doing so I held the stick for her, and she immediately touched it. I'm not sure if she learnt in her previous home or if she learnt by observing Leia. She amazes me with how confident and curious she is - I just have to show her a new toy and she's eager to investigate even if it doesn't sustain her attention.
I'm enjoying watching them engage in parallel behaviours: eating, preening and playing. I'm glad that Leia has another bird with her.