Let's hear it for the squash!!! Many different varieties, all of them nutrient-dense [all that wonderful beta carotene!], low in calories, high water content, low in protein and, to make a long story short: ideal for parrots! And they LOVE them! Now, I know people who feed them raw to the birds but I like to cook them [my birds get raw butternut squash in the gloop] and to vary the kind - so they get pumpkin, Calabaza, acorn, hubbard and spaghetti [which is the one lowest in starch] but, if I find a more uncommon kind, I get it, too.
https://www.verywell.com/winter-squash- ... it-4117503
https://www.thespruce.com/winter-squash ... ns-2217736