This Seeking Tech guide will explain how you can beat Falcon McFly without taking any damage. Use the following video as a reference:
For the first step, take out the smaller enemies quickly and turn into a ball. Once the falcon grabs you with its beak, let go of R2.
Afterwards, head to the left or right wing. Make sure you avoid the pellet spray by turning into a ball. Once you get to the vent, use your spin attack to remove the screw. You then need to jump and use your power-up on the vent.
Next, you can avoid the enemies and head straight to the trampoline. Use your power-up on the head of the falcon to end the first phase of the fight.
For the next section, run horizontally to avoid the rolling birds. You then need to defeat the three screw enemies. You can then turn into a ball when the falcon starts shooting pellets. Do the same thing again when he starts pecking at you.
When his wings get exposed, quickly pick a side. When he starts to shoot pellets, turn into a ball and then make sure to wait until the attack stops. Afterwards, unscrew the vent and then attack it. You can then avoid the enemies and head straight to the trampoline to attack the falcon.
For the final phase, turn into a ball to avoid the pellets. You then need to dodge the rolling birds. When he sends out more small enemies, defeat them quickly and then dodge the big rolling bird. You then need to turn into a ball as the falcon pecks down.
With his wings exposed, pick a side and turn into a ball when he starts shooting. Afterwards, remove the screw and then hit the vent. Run past the final wave of enemies to navigate over to the trampoline.
You then need to attack the bump on its head to end the fight.