There were only a few knights who could kill a gyrfalcon with an arrow, and knights like these were often very well respected within the team. Killing a gyrfalcon was killed the orcs' vision.
The Miracle Spirit would only send out an alert if a large number of enemies were coming. Other than that, it would not interfere with the fight between orcs and humans.
All the head commanders in the spot knew how hard it was to kill a gyrfalcon. When they were flying at full speed, you could not see their body in the sky.
The orc's gyrfalcon had also been trained to dodge arrows, which made killing them even harder.
The sky was also getting dark by that point, but Abel still killed it in one strike. If that gyrfalcon did not get shot right in the head with an arrow, head commander Bodley would just tell himself that Abel was lucky.
