Small pieces of almond or walnuts, cooked plain oatmeal served at room temperature, good quality whole grain breads, tiny piece of string cheese given once weekly. These are his cherished treats in addition to standard foods such as fresh veggies/fruits and pellets.
Actually, we use pine nuts ( different than safflower seeds) for Salty's training sessions. He loves them, but also they are good for immediate treats, meaning if he completes a trick , or or the desired action, the treat can be given immediately. That way Salty can associate the action or whatever with the positive treat. There are things he is equally or more fond of, like chicken leg bones, but they aren't as handy as pine nuts, and Salty takes his own sweet time with each these other treats. Keep trying different treats and eventually you'll figure out the best treat for the occasion. And parrots definitely have a preference, and how they eat each. In example, Salty also loves small bits of walnuts, so much so that he takes forever to fully consume them; we use that particular treat for his in-cage food bowl after he takes a nice spritz of warm ( not hot) water. Salty even knows when I go for the pine nuts and start chopping them up, that it's work time and is especially on the ball. Experiment with all the parrot edible nuts and seeds available in your area. You could also include parrot safe foods from his native range in your search.
My Sam loves walnuts, Senior Bird Nutraberries, apple, pasta, bread, eggplant parmigiana and pizza crust. Also an occasional bit of natural peanut butter on whole wheat bread. He will kill for that!