The long-winged harrier (Circus buffoni) is a common bird of prey species endemic to South America. They are members of the family Accipitridae, under the genus Circus which encompasses other harrier species. Its range encompasses most of South America, in grassland and wetland all across the continent. The long-winged harrier is a carnivorous bird, and will feed on many different animals found in its habitat. Like owls and other harrier species, the long-winged harrier has a distinctive facial disc, which is used to triangulate the bird's hearing while it is hunting. The long-winged harrier is classified as a species of least concern by the IUCN Red List, however their population has been observed to decline due to habitat degradation by human activity. Taxonomy The long-winged harrier was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the falcons, eagles and their relatives in the genus Falco and coined the binomial name Falco buffoni. Gmelin based his description on the "Cayenne ringtail" that had been described in 1781 by the English ornithologist John Latham in his multi-volume work A General Synopsis of Birds. Latham had examined a specimen from Cayenne that formed part of a private collection in London. The specimen had been given the title "Duc de Buffon". The long-winged harrier is now one of 16 harriers placed in the genus Circus that was introduced in 1799 by the French naturalist Bernard Germain de Lacépède. The genus name Circus is derived from the Ancient Greek kirkos, referring to a bird of prey named for its circling flight (kirkos, "circle"), probably the hen harrier. The specific epithet buffoni is from the name of the French naturalist, the Comte de Buffon. The long-winged harrier does not have any recognised subspecies. Description The long-winged is mid-sized bird of prey, and like most birds of prey species, the females are larger than the males. Males will weigh from 390 g to 464 g (13.8 oz to 16.4 oz) and females will be slightly heavier, ranging from 400 g to 645 g (14.1 oz to 22.8 oz). Their length can range between 46 cm and 60 cm (18.1 in to 23.6 in) and their wingspan ranges between 120 cm and 155 cm (47.2 in to 61.0 in). As other harrier species, the lon-winged harrier can be identified by