Undead Fortitude. If damage reduces the zombie roc to 0 hit points, it must make a constitution saving throw with a DC of 5+ the damage taken, unless the damage is radiant or from a critical hit. On a sucess, the zombie roc drops to 1 hit point instead.

Multiattack. The zombie roc makes two attacks: one with its beak and one with its talons.

Beak. Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 27 (4d8 + 9) piercing damage.

Talons. Melee Weapon Attack: +13 to hit, reach 5 ft., one target. Hit: 23 (4d6 + 9) slashing damage, and the target is grappled (escape DC 19). Until this grapple ends, the target is restrained, and the zombie roc can't use its talons on another target.