Keen Sight. The roc has advantage on Wisdom (Perception) checks that rely on sight.
Multiattack. The 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 roc can't use its talons on another target.
At first sight, a roc's silhouette looks much like any other bird of prey. As it descends, however, its unearthly size becomes terrifyingly clear. In flight, a roc's wingspan spreads two hundred feet or more. At rest, perched upon the mountain peaks that are its home, this monstrous bird rivals the oldest dragons in size.