Vocalizations of common kestrels are often one single call repeated in series or not, varied in pitch and frequency, according to the situation, like a simply language of emotion and awareness. They are more vocal during the breeding season, producing a series something like “kik-kik-kik-kik”. In flight, it gives some “kik-kik” calls and alarm calls with a high-pitched “kii-kii-kiikii”. Contact calls between parents and young at nest are a repeated shrill “ki-yiyi”.

Lennart Hessel

National Geographic Society