Yes — corn is safe and universally loved by parrots, though it's starchy enough to count as a treat-vegetable.
Keeper's noteCorn on the cob doubles as a foraging toy — picking kernels off the cob is honest work. Frozen-thawed kernels are a fine shortcut.
Why corn is good for parrots
Fresh corn is non-toxic, easy to digest, and almost no parrot refuses it — which is exactly why it needs rationing. It's high in starch and modest in everything else, so it earns its place as motivation and enrichment rather than a diet staple.
How to serve it
Fresh on the cob (cut into wheels) or frozen-thawed kernels.
Plain only — no butter or salt, so no shared movie corn.
A few times a week, not daily; it's the dessert of vegetables.