Yes — all common squashes (butternut, acorn, spaghetti, summer) are safe and rich in vitamin A. Flesh and seeds included.
Keeper's noteCook the harder winter squashes; summer squash can be raw. The seeds are a safe bonus, like pumpkin seeds.
Why squash is good for parrots
Squash is in the same nutritious, parrot-friendly family as pumpkin and zucchini. Winter squashes like butternut and acorn are especially high in beta-carotene (vitamin A). Flesh and seeds are both edible; cooking softens the harder winter types.
How to serve it
Winter squash: steam or bake plain. Summer squash: raw or cooked.