As far as "big" birds go (in order of normal main macaw breeds) Scarlet - Blue and Golds - Greenwing - Hyacinth. I feel like B&G macaws have the "nicest" bite, don't get me wrong when they bite, it hurts, and can cut and definitely bruises, but I've noticed their beak is more for shredding and crushing. Scarlets tend to cut more, I've been bit a couple times by my friends and he always made me bleed not really bruise, Where as my new Greenwing, she just crushes, and her bite force is so much stronger that I'm sure she'd break a finger before actually cutting it open. Think of it this way.... B&G can open walnuts, Greenwings can open macadamia nuts (B&G's can't and I'm assuming Scarlets can't either) and Hyacinths can open coconuts. And I concur with everyone about smaller birds, you ever been bit by a conure or a parotlet? omg!