Birds
Variable Hawk
Geranoaetus polyosoma · also called red-backed hawk
Soaring on a thermal above open Patagonian terrain, a variable hawk might show pale grey plumage or an almost entirely dark morph, an inconsistency that makes the species one of the hardest South American raptors to identify with confidence.
Overview
The variable hawk, Geranoaetus polyosoma, is a Least Concern bird of prey found across an exceptionally wide range spanning the high Andes to Patagonia. Its extraordinary plumage variation between individuals, broad elevational tolerance, and wide geographic distribution make it one of the more ecologically flexible raptors found anywhere in South America.
A raptor that refuses to look the same twice
Few birds of prey show as much individual plumage variation as the variable hawk, with some birds pale and grey while others appear almost entirely dark, a range of appearances that has long complicated identification in the field.
Status
Least Concern, remaining widespread and secure across its extensive range spanning the Andes and Patagonia.
Variable Hawk: common questions
Why is it called the variable hawk?
Individuals show an extraordinary range of plumage patterns, from mostly pale grey to heavily dark morphs, making the species one of the most variable-looking raptors in South America and a notorious identification challenge.
Why is the variable hawk also called the red-backed hawk?
Some individuals show a rufous patch on the back, a feature that gave rise to the alternative common name red-backed hawk used in parts of its range.
What elevations does the variable hawk use?
It tolerates an unusually wide elevational range, found from lowland Patagonian steppe up to high Andean mountains thousands of metres above sea level.
How does the variable hawk hunt?
It frequently soars on thermals while scanning open ground below, dropping down to catch small mammals, birds, and reptiles.