Colors - I started Salty on one of these
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But now he pretty much hates it and we use it like once every few months. They are plastic and the colors bright. Then we switched to something like this:
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These are wood. 75% of the time Salty gets most right, out of that about 50% are done all correct. And then some nights, he purposely either makes mistakes or refuses the trick, which I always allow him to do. We use these like 1X a week.
Remember - parrots dont see colors like we do, they have extra cones in their eyes and see into the ultraviolet. I suspect thats why he doesn't like the original set up.
You'll find that with regularly scheduled training, Solo will come to anticipate and look forward to his sessions. And Salty does his right after his dinner, so the reward is tiny bits of pine nuts, 1 on 1 time with me and just the joy of using his noodle and solving problems etc. That last one is important for a smart parrot!