Callous Shrieker

Keen Eyes. The shrieker has advantage on Wisdom (Perception) checks that rely on sight. 

Mobile. When the shrieker attacks a creature with an attack, it will not provoke opportunity attacks from that creature for the rest of the turn, regardless of whether the attack hits. 

Thieving. Once per turn when the shrieker hits a creature with a peck attack, it can choose not to deal damage and attempt to steal an item out of the creature's inventory (DM's choice) instead. The shrieker makes a Dexterity (Sleight of Hand) check opposed to the attacked creature's Wisdom (Perception) check. On a success the shrieker steals that item and carries it in its beak.

Multiattack. The shrieker caws and makes two peck attacks.

Peck. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8+4) piercing damage.

Caw. The shrieker caws at a creature that can hear it within 60 ft. of itself. The creature must succeed a DC 14 Wisdom saving throw or has disadvantage on all attack rolls against the Shrieker until the end of the shrieker's next turn. A creature that is immune to fear automatically succeeds the saving throw. If a creature's saving throw is successful, the creature is immune to the shrieker's Caw for the next 24 hours. 

Regurgitate. The shrieker regurgitates partially digested food in a 15 ft. cone. Each creature in the area must make a DC 14 Constitution saving throw or is poisoned until the end of the shrieker's next turn. 

Call the Murder (Recharge 5-6). The shrieker summons a swarm of spectral crows in a 20 ft. radius. Each creature of the shrieker's choice must make a DC 14 Wisdom saving throw. On a failed save, a creature takes 27 (6d8) psychic damage and can't use reactions until the beginning of its next turn. On a successful save a creature takes half as much damage and can't make opportunity attacks until the beginning of its next turn. If the Shrieker is within the radius of effect it can dash as a bonus action until the end of its next turn.