Seventeen subspecies of the American Kestrel are recognized, generally based upon plumage, size, and vocalizations.
Two subspecies of American Kestrel (Falco sparverius) occur in Florida: the northern subspecies (Falco sparverius sparverius) that winters in Florida between September and April, and a resident, non-migratory subspecies, the so called Southeastern American Kestrel (Falco sparverius paulus).
Kestrels seen in Florida during May-June are resident southeastern American Kestrels.

Bird Rookery Swamp, Naples, Florida, USA, 21 November 2012