The cover art suggests that this is a species of "terror bird" (http://en.wikipedia.org/wiki/Terror_bird) formerly of the pampas. Without a mammalian superpredator available in the Cenozoic (wolf, bear, lion), South America evolved a bird to fill the role.
Nice ... but even by boneheaded Hollywood standards it's hard to defend sticking a beast built for the savanna into the Everglades.