American Kestrel
Falco sparverius
Under traditional terminology, the American kestrel is the smallest raptor in the Americas, though the South American spot-winged falconet is almost as small. The American kestrel is sexually dimorphic, although there is some overlap in plumage coloration between the sexes. The bird ranges from 22 to 31 cm (8.7 to 12.2 in) in length with a wingspan of 51–61 cm (20–24 in). The female kestrel is larger than the male, though less so than larger falcons, being typically about 10% to 15% larger within a subspecies. Voice: The American kestrel has three 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.
ID text from Wikipedia, CC BY-SA 4.0
Common Kestrel
Falco tinnunculus
The common kestrel measures 32–39 cm (12+1⁄2–15+1⁄2 in) from head to tail, with a wingspan of 65–82 cm (25+1⁄2–32+1⁄2 in). The female is noticeably larger, with the adult male weighing 136–252 g (4+3⁄4–8+7⁄8 oz), around 155 g (5+1⁄2 oz) on average; the adult female weighs 154–314 g (5+3⁄8–11+1⁄8 oz), around 184 g (6+1⁄2 oz) on average. They are thus small compared with other birds of prey, but larger than most songbirds. Like the other Falco species, they have long wings as well as a distinctive long tail.
ID text from Wikipedia, CC BY-SA 4.0
Where you might meet both
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Play today's Daily BirdPhotos and recordings are credited to their authors under the licence shown. Full profiles: American Kestrel and Common Kestrel.