A bird described as "keen" could also be described as?

When a bird is described as "keen," it encompasses several attributes related to its readiness and eagerness in hunting or flying. The term implies that the bird is not just hungry but also alert and in prime condition for an engaging activity, like hunting.

Being "hungry" indicates that the bird has a strong motivation to hunt, which is often essential for a successful falconry experience. Additionally, the term "sharp-set" suggests that the bird is physically prepared, possibly well-conditioned and focused, indicating its readiness to engage in hunting activities.

"Ready to kill" captures the instinctual nature of a raptor, emphasizing its mindset and physiological state that contribute to its effectiveness as a hunting companion. This readiness is critical in falconry, where the bond between falconer and bird relies on the bird's ability to hunt skillfully.

Thus, describing a bird as keen encompasses all these aspects—its hunger, physical readiness, and instinct to hunt—making the comprehensive choice of "All of the above" the most accurate.