The laughing falcon (Herpetotheres cachinnans) is a medium-sized bird of prey in subfamily Herpetotherinae of family Falconidae, the falcons and caracaras. It is found from Mexico south through Central America and in every mainland South American country except Chile and Uruguay. Taxonomy and systematics Major taxonomic systems place the laughing falcon in subfamily Herpetotherinae with the laughing falcons. Earlier it had been placed in subfamily Falconinae with the "true" falcons. It is the only member of genus Herpetotheres. Though up to six subspecies have been proposed, only two have widespread acceptance: the nominate H. c. cachinnans ((Linnaeus, 1758) and H. c. fulvescens (Chapman, 1915). The laughing falcon's generic name Herpetotheres refers to its preferred food; it is Latinized Ancient Greek, derived from [h]erpeton (ἑρπετόν, "reptile") + therizein (θερίζειν, "to mow down"). Its English name comes from its loud voice, as does the specific epithet cachinnans, Latin for "laughing aloud" or "laughing immoderately". Description The laughing falcon is long and has a wingspan of . Females are slightly larger than males and significantly heavier. Males of the nominate subspecies weigh and females . Subspecies H. c. fulvescens is slightly smaller than the nominate. The sexes of the laughing falcon have the same plumage. Adults of the nominate subspecies have creamy white underparts that vary somewhat among individuals, seasonally, and with feather wear. They have a broad dusky black face "mask" that continues around the neck as a narrow collar. Their crown has dusky black feather shafts that show as narrow streaks, and the rear of the crown has a small bushy crest. Their wings and back are dusky black. Their tail is also dusky black, with four or five white bands, though some individuals have white spots instead. The uppertail coverts are pale buff to cream. The underside of their wing is pale buff, sometimes with some dusky spotting on the underwing coverts, and the flight feathers have cinnamon rufous bases and darker bars. Their iris is dark brown or hazel, their bill is black with a pale yellow to orange-yellow cere, and their feet are usually dull yellow. Immature laughing falcons differ little from adults; they have lighter margins to the back feathers, producing a scalloped effect. Some individuals have cinnamon buff or dusky streaks and spots on their underparts. In flight the laughing falcon shows a rufous patch at the base of the wing's underside and a shape more