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.
right|thumb|Laughing Falcon, Palo Verde Nat'l. Park, Costa Rica
Taxonomy and systematics
The laughing falcon was formally described in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his Systema Naturae. He placed it with the falcons and eagles in the genus Falco and coined the binomial name Falco cachinnans. Linnaeus based his account on information from one of his students, Daniel Rolander, who had visited the Dutch colony of Surinam in South America. The laughing falcon is now the only species placed in the genus Herpetotheres that was introduced in 1817 by the French ornithologist Louis Vieillot. A 2015 molecular phylogenetic study by Jérôme Fuchs and collaborators found that the laughing falcon was sister to the forest falcons in the genus Micrastur.
Major taxonomic systems place the laughing falcon in the subfamily Herpetotherinae with the forest falcons. Earlier it had been placed in the subfamily Falconinae with the "true" falcons.
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".
left|thumb|Painting by [[Andrew Jackson Grayson]]
Description
The laughing falcon is long 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. Some folklore says that the species is capable of predicting rain.
Status
The IUCN has assessed the laughing falcon as being of Least Concern. It has an extremely large range and an estimated population of at least a half million mature individuals, though the latter is believed to be decreasing. No immediate threats have been identified.