GALLIFORM

(order Galliformes), any of the gallinaceous (i.e., fowl-like or chickenlike) birds. The order includes about 240 species, of which the best known are the turkeys (family Meleagrididae); chickens, quail, partridge, pheasant and peacock (Phasianidae); guinea fowl (Numididae); and grouse (Tetraonidae). Lesser known members of the order are the megapodes and the chachalacas, guans, and curassows. Although the hoatzin is here treated with the Galliformes, evidence from studies of egg-white proteins indicate that it should be assigned to the subfamily Crotaphaginae of the family Cuculidae (order Cuculiformes). order of birds (Galliformes) that comprises the gallinaceous (chickenlike) birds; there are about 240 species, including the well-known chickens, pheasants, partridges, quail, and peafowl (family Phasianidae), turkeys (Meleagrididae), guinea fowl (Numididae), and grouse (Tetraonidae). Other, more exotic members of the order are the megapodes (Megapodiidae) of the Australasian region and the South American guans, curassows, and chachalacas (Cracidae). The aberrant South American hoatzin (Opisthocomidae) is sometimes placed in its own order, Opisthocomiformes. Galliforms are heavy-bodied birds with short, rounded wings and strong, four-toed feet, adapted for life on the ground. All gallinaceous birds can fly, but none are long-distance fliers; they burst into quick, short flights to escape from predators. The galliforms are medium-sized birds, weighing from 1.5 ounces (45 g) in the painted quail to 24 pounds (11 kg) in the North American wild turkey. The coloration of females is usually drab, but the males frequently sport highly ornamental plumage. The order is represented in most habitats on all the larger landmasses from the tropics to the subarctic; the ptarmigan (Lagopus) even live above the Arctic Circle. Phasianids have an almost worldwide distribution, while the turkeys are restricted to the Western Hemisphere. Grouse are found throughout the temperate and Arctic regions of both hemispheres, and guinea fowl are found only in Africa south of the Sahara. Galliforms contain two of the birds of greatest economic importance to humankind. These are the chicken (Gallus domesticus), domesticated at least 4,000 years ago from the red jungle fowl (G. gallus), and the turkey. Chickens have been selectively bred to create varieties which produce upwards of 300 eggs a year; other heavy breeds have been developed for meat production. All turkeys are raised for rapid growth and a high meat yield. The guinea fowl is also raised domestically, but to a lesser extent than chickens or turkeys. The majority of terrestrial game birds are members of this order. The common or ring-necked pheasant (Phasianus colchicus), which was introduced to North America, is well established and has become an important game species. Other species popular for sport are certain quail (especially Coturnix and Colinus) and partridges (Perdix and Alectoris). Galliforms are mostly vegetarian, eating seeds, berries, leaves, and the like, but they also eat quantities of insects, worms, and other invertebrates. Many members of the group use their feet to scratch in the vegetation litter and uncover various food sources. The gallinaceous birds show great variety in reproductive behaviour. Some galliforms are monogamous, while many others are polygamous. Monogamy appears in the megapodes, cracids, hoatzin, ptarmigan, guinea fowl, many quail and partridges, and some pheasants. Other pheasants, peafowl, and many grouse are polygamous. In social displays of grouse, the males congregate yearly on a dancing arena, or lek. Each male uses a small area of the lek, where he struts and calls to attract females, which visit the dancing arena and select a male to copulate with. Most gallinaceous birds construct a very limited nest, usually a shallow hole in the ground with a lining of grass or leaves. The only birds that nest in trees are the hoatzin, the cracids, and the horned pheasant (Tragopan). The Megapodiidae, however, have a nesting system different not only from the other galliforms but also from all other birds. They are unique in relying on the heat from solar radiation or fermentation of plant matter to carry out the incubation of their eggs. Some species simply bury the egg in the sand at depths up to three feet (one metre) and pay no further attention to it. When hatched, the young megapodes can dig their way out and forage alone. Other megapodes, such as the mallee fowl, construct mounds of decaying vegetation in which they lay their eggs. Galliforms lay anywhere from two to two dozen eggs. In pheasants, the smaller birds lay from 12 to 20 eggs, but large forms like the great argus may lay only 2. Turkeys and guinea fowl lay between 7 and 20 eggs in a clutch. Most members of the order are indeterminate layers, which explains why they are so useful in commercial egg production. Incubation is usually the task of the female. Except for the hoatzin, gallinaceous chicks are extremely precocious, following the parent and feeding within hours of hatching. The down-covered chicks are protectively coloured but still undergo high mortality rates due to predation. Additional reading H.J. Frith, The Mallee-Fowl: The Bird That Builds An Incubator (1962), is an extensive study of the breeding habits of the megapode Leipoa ocellata. Alexander F. Skutch, Habits of the Chestnut-winged Chachalaca, Wilson Bulletin, 75:262269 (1963), presents information on the breeding habits of Ortalis garrula. Charles Vaurie, Taxonomy of the Cracidae (Aves), Bulletin of the American Museum of Natural History, 138:133259 (1968); and Franois Vuilleumier, Relationships and Evolution Within the Cracidae (Aves, Galliformes), Bulletin of the Museum of Comparative Zoology, Harvard University, 134:127 (1965), are two analyses of the taxonomic relationships within this family. See also Jean Delacour and Dean Amadon, Curassows and Related Birds (1973). Paul A. Johnsgard, The Grouse of the World (1983), includes a lengthy bibliography. Siegfried Klaus et al., Die Auerhhner, new ed. (1986), is a short monograph on the capercaille, and Die Birkhhner, new ed. (1990), is a study of the black grouse. George L. Girard, Life History, Habits, and Food of the Sage Grouse, Centrocercus urophasianus Bonaparte (1937), a brief work, provides insight into the natural history of this grassland species. Gardiner Bump et al., The Ruffed Grouse: Life History, Propagation, Management (1947, reprinted 1978), is a classic study of this woodland grouse. William Beebe, A Monograph of the Pheasants, 4 vol. (191822, reissued 4 vol. in 2, 1990), is a classic work on pheasants, magnificently illustrated with colour plates; revised, less technical editions were published with the title Pheasants: Their Lives and Homes, 2 vol. (1926), and 1 vol. (1936). Jean Delacour, The Pheasants of the World, 2nd ed. (1977), is a fully illustrated treatment of the group, leaning heavily toward aviculture. Philip Wayre, A Guide to the Pheasants of the World (1969), is an extensively illustrated work with emphasis on conservation and on breeding in captivity. Johnsgard's The Pheasants of the World (1986) and The Quails, Partridges, and Francolins of the World (1988) are companion volumes. Herbert L. Stoddard, The Bobwhite Quail: Its Habits, Preservation and Increase (1931, reprinted 1978), is an important book on this game species. Henry S. Mosby and Charles O. Handley, The Wild Turkey in Virginia (1943), is a broad study of the natural history of Meleagris gallopavo. A.W. Schorger, The Wild Turkey: Its History and Domestication (1966), is primarily a historical treatise. William Beebe, A Contribution to the Ecology of the Adult Hoatzin, Zoologica, 1:4566 (1909), and Tropical Wildlife in British Guiana (1917), pp. 155182, present information from the author's field observations of the hoatzin. Franois Haverschmidt The Editors of the Encyclopdia Britannica