A chirping sound from Apple AirPods most commonly indicates that their battery is running low. Users can check this by opening the charging case near the paired phone and viewing the battery status. However, low power is not the only possible explanation.
AirPods may continue making sounds after being connected to power if there are interruptions in the electricity supply, power fluctuations or other battery-related problems. Connectivity issues can also trigger a sound, such as when Bluetooth is switched off on the paired iPhone. Accidentally rubbing the earbuds together can produce noise too.
Some sounds are part of the earbuds' normal operation. AirPods Pro 2 and AirPods Pro 3 support Apple's clinical-grade Hearing Aid feature, and Apple says these models may periodically play a quiet chime while inside their charging case. The sound is intended to help ensure that the microphones and speakers are working properly for hearing-test results.
Louder or more persistent noises can have other causes. AirPods may produce an intense sound when the Find My feature is activated, helping users locate misplaced earbuds. Piercing feedback can occur after water damage or when the earbuds are obstructed by dirt and debris. On AirPods Pro, poorly fitting silicone tips can also cause high-pitched sounds because they fail to create a proper seal. Trying another included tip, using a third-party option or having the earbuds inspected at an Apple Store may help in that situation.
Charging case sounds can be disabled from the connected device. With the AirPods case open, go to Settings on the paired iPhone, tap the AirPods name, open Audio & Routing and switch off Enable Charging Case Sounds. This setting can prevent charging-related chirps, although it will not necessarily eliminate louder noises caused by water damage or other physical problems.
Sources: Engadget.