A bird that is "keen" could be described as which of the following?

A bird that is described as "keen" encompasses several qualities that align with its state of readiness and eagerness. When a bird is keen, it typically indicates that it is alert and enthusiastic, especially in the context of hunting or falconry.

Being "hungry" suggests that the bird has a strong desire or motivation to catch prey, which aligns with its instinctual behavior. This hunger can result in heightened focus and engagement, essential traits for an effective hunting bird.

The term "sharp-set" implies that the bird is physically and mentally prepared. It means the bird is fit, focused, and in prime condition to track and pursue its quarry. This readiness is crucial for successful hunting.

"Ready to kill" conveys the bird's strong predatory instincts. A keen bird is not only prepared to hunt but also shows an eagerness and determination to capture its prey. This aspect is vital for falconers to understand, as the bird's mindset greatly affects performance during hunts.

Therefore, the correct answer signifies that describing a bird as "keen" captures all these aspects—its hunger, physical readiness, and predatory drive. Each of these attributes contributes to a bird's overall alertness and effectiveness as a hunter.