Flyby. The owl doesn't provoke opportunity attacks when it flies out of an enemy's reach.

Keen Hearing and Sight. The owl has advantage on Wisdom (Perception) checks that rely on hearing or sight.

Talons. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 4 (1d4+2) slashing damage.

Stunning Screech (1/Day): The aberrant owl emits a horrific screech. Each creature within 20 feet of it that can hear it must succeed on a DC 14 Constitution saving throw or be stunned until the end of the owl's next turn.

Acid Spew (1/Day): The aberrant owl spews a bubble of acid at one creature within range, or two creatures within range that are within 5 feet of each other. A target must succeed on a Dexterity saving throw or take 1d6 acid damage.