Ambusher. In the first round of a combat, the kenku has advantage on attack rolls against any creature it surprised.
Mimicry. The kenku can mimic any sounds it has heard, including voices. A creature that hears the sounds can tell they are imitations with a successful DC 14 Wisdom (Insight) check.
Saves. Kenku Charisma save is +2
Spellcasting. The bard is a 2nd-level spellcaster. Its spellcasting ability is Charisma (spell save DC 10, +2 to hit with spell attacks). It has the following bard spells prepared that it can cast with its Dulcimer that its proficient with:
Cantrips (at will): light, mending, vicious mockery
1st level (3 slots): bane, dissonant whispers, healing word
Magical Recovery. When the Kenku finishes a short rest, it can recover spell slots. The spell slots can have a combined level that is equal to or less than half it’s level (rounded up), and none of the spell slots can be 6th level or higher. Once the sidekick uses this ability, it can’t use it again until it finishes a long rest.
Shortsword. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage.
Shortbow. Ranged Weapon Attack: +5 to hit, range 80/320 ft., one target. Hit: 6 (1d6 + 3) piercing damage.