The hawks can be divided into three groups—longwings, shortwings, and broadwings. The hawks in each of these three categories display different traits because of adaptation to their hunting environments and prey. Longwings are falcons, such as the peregrine, the saker, and the gyrfalcon. They mainly hunt other birds in flight. Because their pursuit of quarry can take them over considerable distances, longwings are flown over open terrain, such as desert or moorland, so the falconer can keep the falcon in sight. Shortwings and broadwings take predominantly ground game, such as rabbit and hare, or bird species close to the ground, such as a pheasant breaking cover. Physically structured to work in enclosed, wooded countryside, shortwings—which are the true hawks such as goshawks or sparrowhawks—usually hunt from trees, or directly from the gloved fist of the falconer. Finally, the broadwinged group includes eagles and buzzards. The broad wing-bases enable them to soar and they are best suited to hunting in rolling countryside and mountainous terrain, although buzzards can also hunt in wooded areas.

In some countries falconers may legally trap wild hawks, while in others only hawks bred in captivity may be used. In Britain licenses to take hawks from the wild were issued up until the 1980s, but, when sufficient numbers of hawks were domestically produced to meet the demand of falconers, the British government ceased to issue these licenses. In the United States hawks may still be taken from the wild under permit. A system of grading for falconers exists in the United States whereby a novice falconer is apprenticed to a more experienced general or master falconer for a period of two years. The only type of hawk that apprentices in the United States are permitted to train is a wild hawk that was trapped during its first year (before it entered the breeding stock of the species). Apprentices are not, however, allowed to take a young hawk from the nest or to purchase one bred in captivity, because if a hawk acquired from these sources is lost before its training has been completed, it will be unable to hunt for itself. General falconers (with two or more years of experience) and master falconers (seven or more years) in the United States can acquire permits to take wild hawks from the nest, or they may buy a captive-bred hawk. Other parts of the world regulate the taking of wild birds of prey according to the rarity of the species concerned and, in some cases, the experience or credentials of the falconer.

Hawks were first bred in captivity in some number by falconers in the late 1960s and early 1970s in Britain, the United States, and Germany. This occurred in response to a dramatic decline in the numbers of some species of wild hawks—especially the peregrine falcon—caused by pesticides such as DDT that made their way into the food chain and thinned the eggshells of wild birds, which thereby caused the eggs to fail. The availability of domestically produced hawks changed the face of falconry in many countries, as nonindigenous species became available to falconers through a commercial trade in captive-bred hawks.

Captive-bred hawks reared by their parents in aviaries are no easier to train than wild-taken hawks, as the taming process necessary to overcome the hawk's natural wariness of humans is the same. Some species of hawks are by temperament easier to train than others. The most popular hawk used in falconry in Britain is the Harris' hawk, which is native to Central and South America, as well as to the Southwest of the United States. It is widely bred in captivity in the United Kingdom and has a placid temperament, which makes its training comparatively straightforward. The traditional hawks employed in the sport worldwide are peregrine falcons, goshawks, and sparrowhawks; while these species are unsuitable for novices, they are still the most commonly flown throughout the world by experienced falconers.