The Variable Hawk is well-named, exhibiting perhaps the greatest variety of plumage patterns of any species of hawk. It occurs throughout the Andes and in the temperate regions of southern South America. Much debate has centered on the taxonomy of this species, and it frequently has been divided into two species - the widespread, smaller, and more slender "Red-backed" Hawk (Buteo polyosoma) and the larger, heavier "Puna" Hawk (Buteo poecilochrous) of the Andes. The situation is complicated by extensive, parallel plumage variation in the two groups as well as variation in size and structure with latitude and elevation, and controversy continues to swirl around the question of whether poecilochrous in fact is distinguishable from other Variable Hawks. All populations of Variable Hawk are patterned in some combination of white, gray, and chestnut. Pale morphs are whitish below and gray above; in this morph, females also have a red back. Dark morphs are darker gray overall, and females have chestnut extending onto the chest. Variable Hawks occupy open habitats at all elevations, where they prey on mammals and other small animals spotted from the air. They build large stick nests on any elevated structure available, and sometimes breed cooperatively.