<Li> Falco peregrinus cassini, described by Sharpe in 1873, is also known as the Austral peregrine falcon . It includes kreyenborgi, the pallid falcon, a leucistic morph occurring in southernmost South America, which was long believed to be a distinct species . Its range includes South America from Ecuador through Bolivia, northern Argentina, and Chile to Tierra del Fuego and the Falkland Islands . It is non-migratory . It is similar to nominate, but slightly smaller with a black ear region . The variation kreyenborgi is medium grey above, has little barring below, and has a head pattern like the saker falcon, but the ear region is white . </Li> <Li> Falco peregrinus ernesti, described by Sharpe in 1894, is found from Indonesia to Philippines and south to Papua New Guinea and the nearby Bismarck Archipelago . Its geographical separation from nesiotes requires confirmation . It is non-migratory . It differs from the nominate subspecies in the very dark, dense barring on its underside and its black ear coverts . </Li> <Li> Falco peregrinus furuitii, described by Momiyama in 1927, is found on the Izu and Ogasawara Islands south of Honshū, Japan . It is non-migratory . It is very rare, and may only remain on a single island . It is a dark form, resembling pealei in colour, but darker, especially on tail . </Li> <Li> Falco peregrinus japonensis, described by Gmelin in 1788, includes kleinschmidti, pleskei, and harterti, and seems to refer to intergrades with calidus . It is found from northeast Siberia to Kamchatka (though it is possibly replaced by pealei on the coast there) and Japan . Northern populations are migratory, while those of Japan are resident . It is similar to peregrinus, but the young are even darker than those of anatum . </Li>

Why is the peregrine falcon the fastest bird