The Bug:

Sculk sensors are not activated upon parrots sitting on or leaving your shoulder.

Steps to Reproduce:

• Tame a parrot and make it leave / sit on your shoulder.
  →  Notice how the sculk sensor does not activate upon doing either of these things.

Additional Information:

Quote from the 20w49a Changelog, "A vibration is anything that causes physical motion". I would definitely consider this as physical motion, as the parrot is physically leaving / sitting on your shoulder.