What is the primary reason Goshawks need longer field jesses compared to Falcons?

Goshawks require longer field jesses primarily because they are held on the fist when hunting, which facilitates better control of the bird during the hunt. The design of the jesses allows falconers to securely manage a Goshawk while simultaneously allowing for its agility and speed.

Holding a Goshawk on the fist is essential because these birds engage in hunting techniques that are more aggressive and involve closer proximity to the falconer compared to many falcons. This demand for close handling during active hunting scenarios means that a longer jesse provides better restraint and security, ensuring that the bird can be safely controlled without hindering its natural movements when needed.

In contrast, the other answer choices do not address the specific reason related to the jesses. While Goshawks might be heavier than certain falcons, the weight alone is not the primary factor for the length of the jesses. Their flight altitude does not demand longer jesses, and though they may have different hunting styles, this alone does not dictate the need for longer jesses in practical falconry use. The key factor remains the necessity for stable handling during hunting activities.