Galliformes
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 Wild Turkey, Meleagris gallopavo
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Megapodiidae |
Galliformes is an order of chicken-like birds, characterized by stocky built, small head, strong feet, and often short bills and wings, and adult males have sharp horny spur on the back of each leg. This order contains such important domestic and game birds as turkeys, grouse, chickens, quails, and pheasants.
Galliformes are found on every continent except Antarctica. However, some families are limited to a single continent or area, with the megapodes (Megapodiidae, mound-builders) in Australasia, cracids (Cracidae, curassows and relatives) in Central and South America, turkeys (Meleagrididae) in North America, New World quails (Odontophoridae) in North and South America, and guinea-fowl (Numididae) in sub-Saharan Africa (Grzimek et al. 2004). Grouse (Tetraonidae) are found in North America and Eurasia and pheasants and partridges (Phasianidae) are found in Africa, Eurasia, and Australasia.
Galliformes have historically been important for food and as game birds. A number of species have been domesticated, including chickens, turkeys, and guinea fowl, and eggs are a popular food staple. Many are hunted for sport, including a number of species that are reared to be released for hunting. Among the birds that are hunted are wild turkeys, pheasants, and partridges.
Hunting and egg collecting has led to over-exploitation of various wild species, and combined with habitat destruction, today 104 of the 281 extant species are listed as Threatened or Near Threatened (Grzimek et al. 2004).
Description
Galliformes are medium to large size birds. The smallest are the quails, with the most diminutive being the Asian blue quail, Coturnix chinensis, which is about 12.5 centimeters (5 inches) long and 28 to 40 grams (1 to 1.4 ounces in weight. The largest is the North American wild turkey, Meleagris gallopavo, wild specimens of which may weigh as much as 14 kilograms (about 30.5 pounds) and may exceed 120 centimeters (47 inches) in length. Domestic varieties of the wild turkey can attain 20 kilograms (44 pounds) (Grzimek et al. 2004). A male green peafowl, Pavo muticus, can reach 250 centimeters (98 inches) in length, although this includes the immense tail, which may more than half of the length (Grzimek et al. 2004).
Members of Galliformes tend to have a stocky body, small head, and a short bill that is often downcurved (Grzimek et al. 2004). Galliformes also tend to have large and strong feet that allows them to dig for seeds and roots that are inaccessible to many other animals (Grzimek et al. 2004). Adult male Galliform birds have a sharp horny spur on the back of each leg, which they use for fighting. Galliformes have a flexible, roomy crop that can be extended to cache food and have a strong gizzard to grind down seeds, nuts, and tough fibers (Grzimek et al. 2004).
Most Galliform genera are large in body with thick necks and moderately long legs and with rounded wings. Grouse, pheasants, francolins, and partridges are typical in their outwardly corpulent silhouettes.
Some Galliformes are adapted to grassland habitats and these genera are remarkable for their long, thin necks, long legs, and large, wide wings. Thus, wild turkey, crested fireback pheasant, typical peafowl, and vulturine guineafowl are outwardly similar in their convergent body types.
Vegetarian and slightly omnivorous genera are typically stoutly built and have short thick bills primarily adapted for foraging on the ground for rootlets or the consumption of other plant material such as heather shoots. The young birds will also take insects.
Typical peafowl (Pavo), most of the so-called peacock-pheasants (Polyplectron), the Bulwer's Pheasant (Lophura bulweri), the ruffed pheasants (Chrysolophus) and the hill partridges (Arborophila) have narrow, relatively delicate bills, poorly suited for digging. These Galliform genera prefer instead to capture live insects in leaf litter, in sand and in shallow pools or along stream banks. These genera are also outwardly similar in that they each have exceptionally long, delicate legs and toes and the tendency to frequent seasonally wet habitats to forage, especially during chick-rearing.
Male Galliformes have various adornments to attract females, including bright colors, unusually shaped tail feathers, crests, wattles, dewlaps, combs, white patches on the wings or tails, and other markings (Grzimek et al. 2004). Curassows have colorful knobs (ramphothecae) on their bills that grow larger as the birds grows older (Grzimek et al. 2004).
Diet and behavior
Peafowl, junglefowl, and most of the sub-tropical pheasant genera have very different nutritional requirements from typical Palearctic genera. The Himalayan monal (Lophophorus impejanus) has been observed digging in the rotting wood of deadfall in a similar manner to woodpeckers, even bracing itself with aid of its squared tail.
The cheer pheasant (Catreus wallichi), crested argus (Rheinardia ocellata), the enigmatic crested wood partridge (Rollulus roulroul) and the crested guineafowl (Guttera pucherani) are similar ecologically to the Himalayan monal in that they too forage in rotting wood for termites, ant and beetle larvae, mollusks, and crustaceans, as as foraging in the nests of rodents.
The Lady Amherst's pheasant (Chrysolophus amherstiae), green peafowl (Pavo muticus/superspecies complex), Bulwer's pheasant, and the crestless fireback (Lophura erythrophthalma) are notable for their aptitude to forage for crustaceans such as crayfish and other aquatic small animals in shallow streams and among rushes in much the same manner as some members of the rail family (Rallidae).
The tragopans (Tragopan), Mikado pheasant, and several species of grouse and ptarmigan are exceptional in their largely vegetarian and arboreal foraging habitats. But many species of galliformes, for example the long-tailed pheasants of the genus Syrmaticus, find a great deal of their daily nutritional requirements in the tree canopies especially during the snowy and rainy periods when foraging on the ground is dangerous and less than fruitful for a variety of reasons. The great argus and crested argus may do most of their foraging during rainy months in the canopy of the jungle as well.
Although members of the Syrmaticus are capable of subsisting almost entirely on vegetarian materials for months at a time, this is not true for many of the subtropical genera. For example, the two Argus genera are known to forage on slugs, snails, ants, and amphibians to the exclusion of plant material. How they forage in the forest canopy during the rainy months is unknown but is a compelling issue for future investigations.
To aid digestion, Gallinaceous birds will regularly swallow small stones to serve as grit in the strong gizzard (Grzimek et al. 2004).
Species that exhibit the least sexual dimorphism tend to be monogamous, and those in which has the male is more adorned with resplendent plumage tend to be polygynous (Grzimet et al. 2004). Unlike many nonpasserine birds, an important part of the territorial ownership and displays involves calls (Grzimek et al. 2004).
Most of these birds are more or less resident, but some of the smaller temperate species (such as quail) do migrate over considerable distances. Altitudinal migration is evidently quite common among mountain species and a few species of subtropical and near arctic regions must reach their watering and/or foraging areas through sustained flight.
Species known to make extensive flights include the ptarmigans, sage grouse, crested wood partridge, green peafowl, crested argus, mountain peacock pheasant, koklass, Reeves's pheasant, and green junglefowl. Other species, for example most of the toothed quails also known as New World Quails, the enigmatic African stone partridge, guineafowls, and eared-pheasants are all notable for their daily excursions on foot which may take them many miles in a given day. Most species that show only limited sexual dimorphism are notable for the great amount of locomotion required to find food throughout the majority of the year.
Those species that are highly sedentary, but with marked ecological transformations over seasons, exhibit marked distinct differences between the sexes in size or appearance. Eared Pheasants, guineafowls, snow partridges, and toothed quails are examples of limited sexual differences and requirements for traveling over wide terrain to forage.
The bronze-tailed peacock pheasant, snow partridge, painted spurfowl (Galloperdix), and crimson-headed partridge (Haematortyx sanguiniceps) are notable in their habit of not only moving by foot but also in the air as pairs in the manner of doves.
Evolution and classification
Fossils show predecessors to the Galliformes as far back as the Eocene period, some 50 to 60 million years ago.
Galliformes are placed into two tribes. The Craci includes the megapodes, guans, curassows, and chachalacas. The Phasiani includes turkeys, New World quails, grouse, pheasants, partridges, and guinea fowl. These two groups are distinguished by the hind toe (hallux), which is above the other toes in the Phasiani, but in line with the other toes in the Craci (Grzimet et al. 2004).
Different classifications are recognized. Myers et al. (2006) and Grzimek et al. (2004) recognize five families of Galliformes:
- Family Numididae (guineafowl)
- Family Odontophoridae (New World quails)
- Family Phasianidae (turkeys, grouse, pheasants, and partridges)
- Family Cracidae (chachalacas, curassows, and guans)
- Family Megapodiidae (megapodes)
Another classification categorizes Galliformes into eight families:
- Family: Numididae (guineafowl)
- Family: Odontophoridae (New World quails)
- Family: Phasianidae (junglefowl, including the wild form of the domestic chicken, as well as partridges, pheasants, quail, and allies.)
- Family: Cracidae (chachalacas, curassows, and guans)
- Family: Megapodiidae (megapodes—mound-builders)
- Family: Tetraonidae (grouse)
- Family: Meleagrididae (turkeys)
- Family: Mesitornithidae (mesites—may actually be more closely related to gruiform birds)
The buttonquail family is traditionally listed among the Galliformes, but many authorities now regard it as sufficiently different to list it as a separate order. Similarly, the hoatzin was formerly listed here, but DNA comparison indicates that its affinities lie elsewhere (though exactly where is not yet wholly clear).
The Anseriformes (ducks and their allies) and the Galliformes together make up the Galloanserae. They are basal among neognathous birds, and normally follow the Paleognathae (ratites and tinamous) in bird classification systems.
ReferencesISBN links support NWE through referral fees
- Grzimek, B., D. G. Kleiman, V. Geist, and M. C. McDade. Grzimek's Animal Life Encyclopedia. Detroit: Thomson-Gale, 2004. ISBN 0307394913.
- Kriegs, J. O., A. Matzke, G. Churakov, A. Kuritzin, G. Mayr, J. Brosius, and J. Schmitz. 2007. Waves of genomic hitchhikers shed light on the evolution of gamebirds (Aves: Galliformes). BMC Evolutionary Biology 7: 190. Retrieved December 11, 2007.
- Myers, P., R. Espinosa, C. S. Parr, T. Jones, G. S. Hammond, and T. A. Dewey. 2006. Order Galliformes. The Animal Diversity Web (online). Retrieved December 11, 2007.
External links
All links retrieved April 17, 2024.
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