Which of the following species is NOT known for having completely feathered tarsi?

The Cooper's hawk is not known for having completely feathered tarsi, distinguishing it from the other species listed. In falconry and ornithology, tarsi refer to the part of the bird's leg that is typically covered in feathers. The Ferruginous hawk, Golden eagle, and Rough-legged hawk all possess fully feathered tarsi, which helps them in terms of insulation and reduces exposure to the elements while hunting or perching. The lack of feathering in the tarsi of the Cooper's hawk is an adaptation that might enhance its agility and hunting capabilities in its forested habitat. This detail is significant for falconers and birdwatchers alike, as it aids in the identification and understanding of various raptor species.