Avium Canticum

The target creature can hear bird sounds within range that lasts for the duration. It’s volume can range from a whisper to a scream. The sound continues unabated throughout the duration, or you can make discrete sounds at different times before the spell ends.

If a creature uses its action to examine the sound, the creature can determine that it is an illusion with a successful Intelligence (Investigation) check against your spell save DC. If a creature discerns the illusion for what it is, the illusion becomes faint to the creature.