Type Magical beast
CR 6
Environment warm plains and deserts

Source: The Sixfold Trial, pg(s). 88-89

A stymphalides is a carnivorous bird of prey, resembling an ibis or crane that has razor-sharp steel feathers and beak, similar to the metallic hide of a gorgon. An average stymphalides is about two and a half feet tall and weighs no more than 40 pounds. These creatures haunt arid plains and coastlines in large swarms, relying on numbers to overwhelm prey. Occasional stymphalides grow to giant size, sometimes larger than an axe beak. [1]

A giant stymphalides is a large version of the stymphalides, reaching up to 13 feet tall, weighing over 250 pounds, and with wingspans of 25 feet or more. Giant stymphalides are extremely rare, and prefer to make their homes deep within desolate mountains and even savage and inhospitable planar realms.[1]