Life Drain. Melee Spell Attack: +4 to hit, reach 5 ft., one creature.
Hit:10 (3d6) necrotic damage. The target must succeed on a DC 10 Constitution saving throw or its hit point maximum is reduced by an amount equal to the damage taken. This reduction lasts until the creature finishes a long rest. The target dies if this effect reduces its hit point maximum to 0.
Flyby. The owl doesn't provoke oportunity attacks when it flies out of an enemy's reach.
Keen Hearing and Sight. The owl has advantage on WIS (Perception) checks that rely on hearing or sight.,
Talons. Melee Weapon Attack: +3 to hit, reach 5ft, one target. Hit: 8 (1d1) slashing damage