In North America, the prairie falcon and the gyrfalcon can capture small mammal prey such as rabbits and hares (as well as the standard gamebirds and waterfowl) in falconry, but this is rarely practiced. Young falconry apprentices in the United States often begin practicing the art with American kestrels, the smallest of the falcons in North America; there is debate on this, as they are small fragile birds and can die easily if neglected. Small species, such as kestrels, merlins and hobbys are most often flown on small birds like starlings or sparrows but can also be used for recreational bug hawking – that is, hunting large flying insects such as dragonflies, grasshoppers, and moths. Owls are not closely related to hawks or falcons. There is little written in classic falconry that discusses the use of owls in falconry. However, there are at least two species that have successfully been used, the Eurasian eagle owl and the great horned owl. Successful training of owls is much different from the training of hawks and falcons, as they are hearing- rather than sight-oriented. (Owls can only see black and white, and are long-sighted.) This often leads falconers to believe that they are less intelligent, as they are distracted easily by new or unnatural noises and they do not respond as readily to food cues. However, if trained successfully, owls show intelligence on the same level as that of hawks and falcons. The "Aquila" (all have "booted" or feathered tarsus) genus has a nearly worldwide distribution. The more powerful types are used in falconry; for example golden eagles have reportedly been used to hunt wolves in Kazakhstan, and are now most widely used by the Altaic Kazakh eagle hunters in the western Mongolian province of Bayan-Ölgii to hunt foxes, and other large prey, as they are in neighbouring Kyrgyzstan. Most are primarily ground-oriented but will occasionally take birds. Eagles are not used as widely in falconry as other birds of prey, due to the lack of versatility in the larger species (they primarily hunt over large open ground), the greater potential danger to other people if hunted in a widely populated area, and the difficulty of training and managing an eagle. There are a little over 300 active falconers using eagles in Central Asia, with 250 in western Mongolia, 50 in Kazakhstan, and smaller numbers in Kyrgyzstan and western China.