In science, bird sounds are usually visualised using waveforms or spectrograms (also called sonograms). These graphic illustrations depict properties of the sounds along a time axis. While waveforms only show the sound pressure (“loudness”), spectrograms also show the frequency (“pitch”).

Pitch is measured in Hertz (Hz). This number indicates how many times the sound wave of the tone rises and falls per second. The visual depiction of both pitch and the time axis can vary considerably based on the height and duration of the singing by each bird species.

While some birds, like the blue tit, have vocal units lasting only 2 seconds, others, such as the male skylark, can sing continuously for two to five minutes. On the other hand, certain birds occasionally sing at high pitches, like the robin, while others, like the common raven, produce much lower tones.

The visual representation of bird sounds can also assist humans in better recognising the differences between songs. Additionally, it aids in detecting bird sounds that extend beyond one’s own range of acoustic perception.

Listen to and watch the sounds of the birds below…