Yes — sweet potato is an outstanding vitamin A source, one of the very best vegetables for parrots.
Keeper's noteCooked and cooled, or raw grated. Mashed plain sweet potato is the base of half the good 'birdie bread' recipes out there.
Why sweet potato is good for parrots
Sweet potato is the single richest common-food source of beta-carotene, directly targeting the vitamin A deficiency so common in pet parrots. Cooked, it's soft, sweet, and almost universally accepted — including by stubborn seed-junkies mid-conversion.
How to serve it
Steam or bake plain, cool, and cube — no butter, sugar, or marshmallow.
Raw is safe too: offer grated or in thin matchsticks.