Hertzel Symptom

Hertzl (Hertzl, Hertzel) symptom - inarticulate sounds emitted by birds living in city squares and parks. This phenomenon is due to the fact that birds perceive the sounds of urban transport and car engines as alarm signals and react to them by emitting specific cries that can be attributed to such situations. In addition, birds often mistake domestic cats, dogs, or other birds for predators and also produce an inarticulate sound that may resemble the same Hertzl symptom.

Experimentally, the Hertzl symptom can be created using a highly vibrating sound source, e.g.