The duck has no system of defense like a porcupine so their instinct is thus different
Step-by-step explanation:
A porcupine defends itself from an attacker by keeping its face hidden on the bare ground and keeping its belly down to the ground while shooting up the quills on its back.
The quills are not poisonous but still can kill an assailant.
The duck has no such form of defense so it often has the instinct of hiding and not doing that position.
The duck usually tries to run away from the danger as it has no advantage in standing the ground to defend.