Vocalizations
The American Kestrel has four basic vocalizations – the "klee" or "killy", the "whine", and the "chitter." The "klee" is usually delivered as a rapid series – klee, klee, klee, klee when the kestrel is upset or excited. This call is used in a wide variety of situations and is heard from both sexes, but the larger females typically have lower-pitched voices than the males. The "whine" call is primarily associated with feeding, but is also uttered during copulation. The "chitter" is used in activities which involve interaction between male and female birds, including courtship feeding, copulation, and the feeding of nestlings. Nestlings can produce calls similar to those of adults at 16 days old.
Read more about this topic: American Kestrel, Description