The highest human whistle ever recorded reached 10,599 Hz, which is higher than the chirps of many birds.

The world record for the highest whistle was set by Jennifer Davies of Canada on October 29, 2010. During a session in Loughton, Essex, UK, she reached a frequency of 10,599 Hz. This frequency corresponds to the note C9, which is significantly higher than the C8 note that ends a standard 88-key piano. For comparison, a typical human conversation occurs at frequencies between 85 and 255 Hz.Whistling is a form of aerophone where sound is produced by forcing a stream of air through a small opening. To achieve the record-breaking pitch, Davies utilized a technique called 'palate whistling' or 'roof whistling.' This involves positioning the tongue against the hard palate to create an incredibly small resonance chamber. The smaller the volume of this chamber, the higher the frequency of the resulting sound wave.At 10,599 Hz, the sound sits in the upper range of human hearing, which typically caps out at 20,000 Hz for young adults. Many birds, such as the American Robin, produce songs in the 2,000 to 6,000 Hz range. This makes Davies' whistle sharper than most avian vocalizations. Such high-frequency sounds are difficult for the human ear to localize and can often be mistaken for electronic feedback or mechanical noise.