Many mythological creatures have a popularity secondary only to the dragon (the one true global force.) Among them is the griffin, a half-bird-half-cat cut-and-paste. Now, in an alternate Earth, the griffin is a real clade of primarily arboreal mammal, which means ditch the third pair of limbs and justify the "eagle-talons" as something more akin to a raccoon's or a grey fox's (though the Europeans or Africans or Asians who described the griffins had no idea what a raccoon or grey fox looked like, so "eagle-talons" pretty much got stuck.) What's more is that they occupy a niche filled back home by certain clades of parrots.
But for these mammals to fill in such a role requires altering the jawline into something strong and curved. Within the mammal class, is this within the realm of possibility?
Oh, and before any of you bring up the duck-billed platypus, I'm aiming at a parrot angle, not a duck angle.