Galliformes

Life-forms

Superregnum: Eukaryota
Cladus: Opisthokonta
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Classis: Aves
Subclassis: Carinatae
Infraclassis: Neornithes
Parvclassis: Neognathae
Ordo: Galliformes
Familiae: Megapodiidae - Cracidae - Phasianidae - Odontophoridae - Numididae - Mesitornithidae

Name

Galliformes (Temminck, 1820)

Vernacular names
Internationalization
Česky: Hrabaví
Dansk: Hønsefugle
Deutsch: Hühnervögel
English: Gamebird
Hrvatski: Kokoške
Italiano: Galliformi
Lietuvių: Vištiniai Paukščiai
Nederlands: Hoendervogels
‪Norsk (bokmål)‬: Hoendervogels
Polski: Grzebiące
Português: Galináceo
Русский: Куриные
Suomi: Kanalinnut
Svenska: Hönsfåglar
Türkçe: Tavuksular
Українська: Куроподібні

Galliformes are an order of birds heavy-bodied ground-feeding domestic or game birds, containing turkey, grouse, chicken, quail, ptarmigan, partridge, pheasant, and the Cracidae. Common names are gamefowl or gamebirds, landfowl, gallinaceous birds or galliforms. "Wildfowl" or just "fowl" are also often used for Galliformes, but usually these terms also refer to waterfowl (Anseriformes), and occasionally to other commonly hunted birds.

Included species

This group has more than 250 living species, one or more of which are found in essentially every part of the world's continents (except for the innermost deserts and perpetual ice). They are more rare on islands, and in contrast to the closely-related waterfowl are essentially absent from oceanic islands—except if introduced there by humans. Several species have been domesticated during their long and extensive relationship with humans.

This order contains four families: family Tetraonidae (including grouse and ptarmigan), family Meleagrididae (including turkeys), family Phasianidae (including quail, partridges, and pheasants), and the family Cracidae (including chachalacas). They are important as seed dispersers and predators in the ecosystems they inhabit and are often reared as game birds by humans for meat and egg consumption and for recreational hunting. All are skilled runners that can fly only a few hundred feet when escaping danger. Males of most species are more colorful than the females. Males often have elaborate courtship behaviors that include strutting, fluffing of tail or head feathers, and vocal sounds. They are mainly non-migratory birds well adapted to the winter climate.

Taxonomy

Kingdom: Animalia phylum: Chordata subphylum: Vertebrata class: Aves order: Galliformes 70 genera 250+ species

Description

They are chicken-like in appearance, with rounded bodies and blunt wings, and range in size from small (6 inches) to large (4 feet). They are mainly terrestrial birds and their wings are short and rounded for short distanced flights.

Lifestyle

Gallinaceous birds are arboreal or terrestrial animals; most do not fly, but walk and run instead for transportation. They live from 5–8 years in the wild and up to 30 years in captivity. They can be found worldwide and in a variety of habitats, including forests, deserts, and meadows. They use visual displays and vocalizations for communication, courtship, fighting, territoriality, and brooding.

They have diverse mating strategies: some are monogamous, while others are polygamous or polygynandrous (that is, when multiple males have a relationship with multiple females) link. Male courtship behavior includes elaborate visual displays of plumage. They breed seasonally in accordance with the climate and lay anywhere from 3-16 eggs per year in nests built on the ground or in trees.

Gallinaceous birds feed on a variety of plant and animal material, which may include fruits, seeds, leaves, shoots, flowers, tubers, roots, insects, snails, worms, lizards, snakes, small rodents, and eggs.

These birds vary in size from the diminutive Asian Blue Quail (Coturnix chinensis) at 12.5 cm (5 in) long and weighing 28–40 g (1–1.4 oz) to the largest extant galliform species, the North American Wild Turkey (Meleagris gallopavo), which may weigh as much as 14 kg (30.5 lb) and may exceed 120 cm (47 in).

The galliform bird species with the largest wing-span and largest overall length (including a train of over 6 feet) is most likely the Green Peafowl (Pavo muticus). Most galliform genera are plump-bodied with thick necks and moderately long legs, and have rounded and rather short wings. Grouse, pheasants, francolins, and partridges are typical in their outwardly corpulent silhouettes. While most galliforms are rather weak-flying, flightless forms are unknown among the living members of the order. The Sylviornis, a huge prehistorically extinct mound-builder relative of New Caledonia, was flightless, but as opposed to most other flightless birds like ratites or island rails which become flightless due to arrested development of their flight apparatus and subsequently evolve to larger size, the Sylviornis seems to have become flightless simply due to its bulk, with the wing reduction following a consequence, not the reason for its flightlessness. There are a number of prehistorically extinct mound-builders from Pacific islands, and these seem to have arrived at flightlessness in the more conventional way.

Adult males of many galliform birds have one to several sharp horny spurs on the back of each leg, which they use for fighting. In several lineages, there is pronounced sexual dimorphism, and among each galliform clade, the more apomorphic ("advanced") lineages tend to be more sexually dimorphic.

Ecology

Most of the galliform 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 amongst montane species and a few species of subtropical and subarctic regions must reach their watering and/or foraging areas through sustained flight. Species known to make extensive flights include the ptarmigans, sage-grouse (Centrocercus), Crested Wood-partridge, Green Peafowl, Crested Argus, Mountain Peacock-pheasant (Polyplectron inopinatum), Koklass (Pucrasia macrolopha), Reeves's Pheasant (Syrmaticus reevesii) and Green Junglefowl (Gallus varius) . Other species—most of the New World quails (also known as the toothed quails), the enigmatic Stone Partridge (Ptilopachus petrosus) of Africa, guineafowl and eared-pheasants (Crossoptilon)—are all notable for their daily excursions on foot which may take them many miles in a given day.

Some Galliformes are adapted to grassland habitat, and these genera are remarkable for their long, thin necks, long legs and large, wide wings. Fairly unrelated species like the Crested Fireback (Lophura ignita), Vulturine Guineafowl (Acryllium vulturinum) and Malleefowl (Leipoa ocellata) are outwardly similar in their body types (see also convergent evolution).

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 and/or appearance. Eared-pheasants, guineafowls, toothed quails and the Snow Partridge (Lerwa lerwa) are examples of limited sexual differences and requirements for traveling over wide terrain to forage.

The Bronze-tailed Peacock-pheasant (Polyplectron chalcurum), Snow Partridge, Painted Spurfowl (Galloperdix lunulata) and the Crimson-headed Partridge (Haematortyx sanguiniceps) are notable in their habit of moving around as pairs not only on foot but also in the air.

Winter ecology

Gallinaceous birds are well adapted to regions with cold winters. Their larger size, increased plumage, and lower activity levels help them to withstand the cold temperatures and conserve energy. Under such conditions, they are able to change their feeding strategy to that of a ruminant. This allows them to feed on and extract energy and nutrients from coarse, fibrous plant material, such as buds, twigs, and conifer needles. This provides a virtually unlimited source of accessible food and requires little energy to harvest. Additionally gallinaceous birds roost beneath the snow and create a thermal microclimate that conserves heat.

Food and feeding

Herbivorous to slightly omnivorous galliforms, comprising the majority of the group, 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.

Peafowl, junglefowl and most of the subtropical 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 to extract invertebrates, even bracing itself with aid of its squared tail. The Cheer Pheasant (Catreus wallichi), Crested Argus (Rheinardia ocellata), the 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, molluscs, crustaceans and young rodents.

Typical peafowl (Pavo), most of the 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 invertebrates 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. The Blue Peafowl (Pavo cristatus) is famed in its native India for its appetite for snakes – even poisonous cobras – which it dispatches with its strong feet and sharp bill. The Lady Amherst's Pheasant (Chrysolophus amherstiae), Green Peafowl (Pavo muticus), 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 amongst rushes in much the same manner as some members of the rail family (Rallidae).
During mating season, the male Capercaille feeds mainly on bilberry leaves, which are toxic to most herbivores

The tragopans (Tragopan), Mikado Pheasant (Syrmaticus mikado) and several species of grouse and ptarmigan are exceptional in their largely vegetarian and arboreal foraging habitats; grouse are especially notable for being able to feed on plants rich in terpenes and quinones – such as sagebrush or conifers –, which are often avoided by other herbivores. But many species of moderate altitudes—for example the long-tailed pheasants of the genus Syrmaticus—also find a great deal of their daily nutritional reqirements 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. Although members of the genus 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 Great Argus (Argusianus argus) and Crested Argus may do most of their foraging during rainy months in the canopy of the jungle as well. There they 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.

Reproduction

Most galliforms are very prolific, with clutches regularly exceeding 10 eggs in many species. In contrast to most birds which are – at least for a particular breeding season – monogamous, galliforms are often polygynous or polygamous. Such species can be recognized by their pronounced sexual dimorphism.

Galliform young are very precocious and will roam their habitat with their mothers – or both parents in monogamous species – mere hours after hatching. The most extreme case are the Megapodidae, where the adults do not brood but leave incubation to mounds of rotting vegetation, volcanic ash or hot sand. The young have to dig their way out of the nest mounds after hatching, but they emerge from the eggs fully feathered and as soon as they leave the mound, they are able to fly for considerable distances.

Systematics and evolution
Despite its distinct appearance, the Wild Turkey is actually a very close relative of pheasants

The living Galliformes were long divided into some 7 or more families. More recently, it is generally believed that the quite distincly-appearing grouse and turkeys do not warrant separation as families due to their quite recent origin from partridge- or pheasant-like birds. As it seems, the turkeys became huge after their ancestors colonized temperate and subtropical North America where pheasant-sized competitors were absent. The ancestors of grouse, on the other hand, adapted to harsh climate and thus grouse could colonize subarctic regions. Consequently the Phasianidae are expanded in current treatments to include the former Tetraonidae and Meleagrididae as subfamilies.[1]

The Anseriformes (waterfowl) and the Galliformes together make up the Galloanserae. They are basal among the living neognathous birds, and normally follow the Paleognathae (ratites and tinamous) in modern bird classification systems. This was first proposed in the Sibley-Ahlquist taxonomy and has been the one major change of that proposed scheme that was almost universally adopted. On the other hand, the Galliformes as they were traditionally delimited are called Gallomorphae in the Sibley-Ahlquist taxonomy, which splits the Cracidae and Megapodidae as an order "Craciformes". This is not a natural group however, but rather an erroneous result of the now-obsolete phenetic methodology employed in the Sibley-Ahlquist taxonomy.[2] Phenetic studies do not distinguish between plesiomorphic and apomorphic characters, which leads to basal lineages appearing as monophyletic groups.

Historically, the buttonquails (Turnicidae), mesites (Mesitornithidae) and the Hoatzin (Opisthocomus hoazin) were placed in the Galliformes too. The former are now known to be shorebirds adapted to an inland lifestyle, whereas the mesites are probably related to at least some of the birds traditionally in the "Gruiformes" assemblage. The relationships of the Hoatzin are entirely obscure, and it is usually treated as a monotypic order Opisthocomiformes to signify this.
[edit] Evolution

Given that the oldest known waterfowl, Vegavis iaai, dates from the Late Cretaceous, galliform ancestors must also have roamed the Earth contemporaneously with animals such as Tyrannosaurus rex.[3]

Indeed, there exist a few fragmentary fossils of putative galliforms from the Cretaceous, of which the most interesting fossil taxon is Austinornis. Formerly referred to as Ichthyornis lentus, Graculavus lentus or Pedioecetes lentus, its partial left tarsometatarsus was found in the Late Cretaceous Austin Chalk near Fort McKinney, Texas. This bird was quite certainly closely related to Galliformes, but whether it was a part of these or belongs elsewhere in the little-known galliform branch of Galloanserae is not clear.[4]

Other Mesozoic fossils are referred to the Galliformes with considerably less certainty: The very enigmatic Gallornis living in today's France some 140–130 Ma (million years ago) was as far as anyone can tell an ornithuran. But although the possibility that it was a very early galliform cannot be positively excluded, its ancient age makes this seem not particularly likely. The case of Austinornis shows that it is certainly possible to confuse a putative galliform with more primitive ornithurans like Ichthyornis.

Specimen PVPH 237 from the Late Cretaceous Portezuelo Formation (Turonian-Coniacian, about 90 Ma) in the Sierra de Portezuelo (Argentina) makes a far more plausible galliform candidate. This is a partial coracoid of a neornithine bird, which in its general shape and particularly the wide and deep attachment for the muscle joining the coracoid and the humerus (upper arm) bone resembles the more basal lineages of galliforms.[5]

The Paleogene had several galliforms of now-extinct families, namely the Gallinuloididae, Paraortygidae and Quercymegapodiidae. In the early Cenozoic, there are some additional birds that may or may not be early Galliformes, though even if they are, it is rather unlikely that these belong to extant families:

* †Argillipes (London Clay Early Eocene of England)
* †Coturnipes (Early Eocene of England, and Virginia, USA?)
* †Paleophasianus (Willwood Early Eocene of Bighorn County, USA)
* †Percolinus (London Clay Early Eocene of England)
* †Amitabha (Bridger middle Eocene of Forbidden City, USA) – phasianid?
* †"Palaeorallus" alienus (middle Oligocene of Tatal-Gol, Mongolia)
* †Anisolornis (Santa Cruz Middle Miocene of Karaihen, Argentina)

From the mid-Eocene onwards – about 45 Ma or so –, modern-type galliforms are known, and these completely replace their older relatives in the early Neogene. Since the earliest representatives of living galliform families apparently belong to the Phasianidae – the youngest family of galliforms -, the other families of Galliformes must be at least of Early Eocene origin but might even be as old as the Late Cretaceous. The ichnotaxon Tristraguloolithus cracioides is based on fossil eggshell fragments from the Late Cretaceous Oldman Formation of southern Alberta, Canada which are similar to chachalaca eggs,[6] but in the absence of bone material their relationships cannot be determined except that they are apparently not from a non-avian dinosaur.

Modern genera of phasianids start appearing around the Oligo-/Miocene boundary, roughly 25–20 Ma. It is not well known whether the living genera of the other, older, galliform families originated around the same time or earlier, though at least in the New World quails, pre-Neogene forms seem to belong to genera that became entirely extinct later on.

A number of Paleogene to mid-Neogene fossils are quite certainly Galliformes, but their exact relationships in the order cannot be determined:
Palaeortyx skeleton, Muséum national d'histoire naturelle, Paris

* †Austinornis (Austin Chalk Late Cretaceous of Fort McKinney, USA) – tentatively placed here, formerly Graculavus/Ichthyornis/Pedioecetes lentus
* †Procrax (middle Eocene? – Early Oligocene) – cracid? gallinuloidid?
* †Palaeortyx (middle Eocene -? Early Pliocene) – phasianid or odontophorid
* †Palaeonossax (Brule Late Oligocene of South Dakota, USA) – cracid?
* †Taoperdix (Late Oligocene) – gallinuloidid? Includes "Tetrao" pessieti
* †Archaealectrornis (Oligocene) – phasianid?
* †Galliformes gen. et sp. indet. (Oligocene) – formerly in Gallinuloides; phasianid?[7]
* †Archaeophasianus (Oligocene? – Late Miocene) – phasianid? (tetraonine?)
* †Palaealectoris (Agate Fossil Beds Early Miocene of Sioux County, USA) – tetraonine?
* †Linquornis (middle Miocene)
* †Palaeoalectoris (Xiacaowan middle Miocene of Sihong, China)
* †Shandongornis (middle Miocene)
* †"Cyrtonyx" tedfordi (Barstow Late Miocene of Barstow, USA)

List of major taxa

For a long time, the pheasants, partridges and relatives were indiscriminately lumped in the Phasianidae, variously including or excluding turkeys, grouse, New World quails and guineafowl, and divided into two subfamilies – the Phasianinae (pheasant-like forms) and the Perdicinae (partridge-like forms). This crude arrangement was long considered to be in serious need of revision, but even with modern DNA sequence analyses and cladistic methods, the phylogeny of the Phasianidae has resisted complete resolution.[8]

A tentative list of the higher-level galliform taxa, listed in evolutionary sequence, is:[8]

* Family †Paraortygidae
* Family †Quercymegapodiidae
* Family †Sylviornithidae – Sylviornis
* Family Megapodidae – mound-builders and scrubfowl, or megapodes
* Family Cracidae – chachalacas, guans and curassows
* Superfamily Phasianoidea
o Family †Gallinuloididae – tentatively placed here
o Family Odontophoridae – New World quail
o Family Numididae – guineafowl
o Family Phasianidae – pheasants, partridges and relatives
+ Subfamily Arborophilinae – jungle- and wood-partridges
+ Subfamily Coturnicinae – Old World quail, scrub-partridges and spurfowl
+ Subfamily Pavoninae – peafowl and ocellated pheasants
+ Subfamily Gallininae – francolins and junglefowl (including chickens)
+ Subfamily Meleagridinae – turkeys
+ Subfamily Perdicinae – grey partridges (probably belong in either Meleagridinae or Phasianinae)
+ Subfamily Tetraoninae – grouse
+ Subfamily Phasianinae – true pheasants

The relationships of many pheasants and partridges are still very badly resolved and much confounded by adaptive radiation (in the former) and convergent evolution (in the latter).[9] Thus, the bulk of the Phasianidae can alternatively be treated as a single subfamily Phasianinae. The grouse, turkeys, true pheasants etc., would then become tribes of this subfamily, similar of how the Coturnicinae are commonly split into a quail and a spurfowl tribe.[10]

Note that the taxon Perdicinae is tentatively limited to the genus Perdix and perhaps one or two others. That "the" partridge of Europe is not closely related to other partridge-like Galliformes is already indicated by its sexually dimorphic coloration and numerous (more than 14) rectrices, traits it shares with the other advanced phasianids. However, among these its relationships are obscure; it is entirely unclear whether it is closer to the turkeys or to certain short-tailed pheasants like Ithaginis, Lophophorus, Pucrasia and Tragopan.[11]

Common species

Grouse and Ptarmigans Family Tetraonidae

Grouse, ptarmigans, and prairie chickens are all chicken-like birds with short, curved, strong bills part of the family Tetraonidae. This group includes 25 species residing mostly in North America. They are mainly ground-dwellers and have short, rounded wings for brief flights. They are well adapted to winter by growing feather “snowshoes” on their feet and roosting beneath the snow. They range in size from the 13-inch White-tailed Ptarmigan to the 28-inch Sage Grouse. Their plumage is dense and soft and is most commonly found in shades of red, brown, and gray in order to camouflage to the ground. They are polygamous and male courtship behavior includes strutting and dancing and aggressive fighting for possession of females. The typical clutch size is between 7 and 12 eggs.

Turkeys Family Meleagrididae

Turkeys are large, long-legged birds that can grow up to four feet in height and weigh up to 30 lbs in the wild. They have a long broad, rounded tail with 14-19 blunt feathers. They have a naked wrinkled head and feathered body. The North American wild turkey - Meleagris gallopavo - has 5 distinct subspecies (Eastern, Rio Grande, Florida a.k.a. Osceola, Merriams, and Goulds). Hybrids also exist where the range of these subspecies overlaps. All are native only to North America, though transplanted populations exist elsewhere. Their plumage differs slightly by subspecies, but is generally dark to black for males, with buff to cream hightlights, and generally drab brown for females. The feathers are quite iridescent and can take on distinct reddish/copper hues in sunlight. Their feathers are well defined with broad, square ends, giving the bird the appearance of being covered in scales. Males have a “beard” of coarse black bristles hanging from the center of their upper breast and tend to have more vibrantly colored plumage than do females. They breed in the Spring and their typical clutch size is between 10 and 12 eggs. The "ocellated turkey" (Meleagris ocellata) is a different species of turkey, and currently exists only in a portion of the Yucutan peninsula. After the 19th and early 20th century wild turkey populations dropped significantly because of hunting and habitat loss. However, populations now flourish again thanks to hunting management and transplanting. The ocellated turkey, not commonly hunted, is currently threatened due to ongoing habitat loss in the Yucutan.

Pheasants, Quail, and Partridges Family Phasianidae

The family is divided into four groups: 30 species of new world quail, residing between Paraguay and Canada, 11 species of old world quails in Africa, Australia, and Asia, 94 species of partridges, and 48 species of pheasants. This family includes a wide range of bird sizes from a 5 ½-inch quail to pheasants up to almost 30 inches. Pheasants and quails have heavy, round bodies and rounded wings. Even though they have short legs, they are very fast runners when escaping predators.

Chachalacas Family Cracidae

Chachalacas are found in the chaparral ecosystems from southern Texas through Mexico and Costa Rica. They are mainly arboreal and make their nests in trees five to fifteen feet above the ground. They are large, long-legged, birds that can grow up to 26 inches long. They have long-tails and are chicken-like in appearance. Their frail looking yet sturdy nests are made out of sticks and leaves. Their clutch size is 3 or 4 eggs. The males make a unique, loud, mating call that given them their name: “cha-cha-la-ca”. Chachalacas feed mainly on berries but also eat insects. They are a popular game bird as their flesh is good to eat. They are also commonly domesticated as pets.

Footnotes

1. ^ Kimball et al. (1999), Dyke et al. (2003), Smith et al. (2005), Crowe et al. (2006a,b)
2. ^ Smith et al. (2005), Crowe et al. (2006a,b)
3. ^ Though not necessarily the same part of the Earth as that particular dinosaur.
4. ^ Clarke (2004)
5. ^ Agnolin et al. (2006)
6. ^ Zelenitsky et al. (1996)
7. ^ Specimen MCZ 342506. A proximal humerus of a bird larger than Gallinuloides: Mayr & Weidig (2004)
8. ^ a b Kimball et al. (1999, 2001), Crowe et al. (2006a,b)
9. ^ Dyke et al. (2003)
10. ^ See e.g. the phylogenies in Kimball et al. (2006) and Crowe et al. (2006a,b)
11. ^ Kimball et al. (1999, 2001), Smith et al. (2005), Crowe et al. (2006a,b)

References

* Agnolin, Federico L.; Novas, Fernando E. & Lio, Gabriel (2006): Neornithine bird coracoid from the Upper Cretaceous of Patagonia. Ameghiniana 43(1): 245–248. HTML fulltext
* Clarke, Julia A. (2004): Morphology, Phylogenetic Taxonomy, and Systematics of Ichthyornis and Apatornis (Avialae: Ornithurae). Bulletin of the American Museum of Natural History 286: 1–179 PDF fulltext
* Crowe, Timothy M.; Bloomer, Paulette; Randi, Ettore; Lucchini, Vittorio; Kimball, Rebecca T.; Braun, Edward L. & Groth, Jeffrey G. (2006a): Supra-generic cladistics of landfowl (Order Galliformes). Acta Zoologica Sinica 52(Supplement): 358–361. PDF fulltext
* Crowe, Timothy M.; Bowie, Rauri C.K.; Bloomer, Paulette; Mandiwana, Tshifhiwa G.; Hedderson, Terry A.J.; Randi, Ettore; Pereira, Sergio L. & Wakeling, Julia (2006b): Phylogenetics, biogeography and classification of, and character evolution in, gamebirds (Aves: Galliformes): effects of character exclusion, data partitioning and missing data. Cladistics 22(6): 495–532. doi:10.1111/j.1096-0031.2006.00120.x PDF fulltext
* Dyke, Gareth J; Gulas, Bonnie E. & Crowe, Timothy M. (2003): Suprageneric relationships of galliform birds (Aves, Galliformes): a cladistic analysis of morphological characters. Zool. J. Linn. Soc. 137(2): 227–244. doi:10.1046/j.1096-3642.2003.00048.x PDF fulltext
* Kimball, Rebecca T.; Braun, Edward L.; Zwartjes, P.W.; Crowe, Timothy M. & Ligon, J. David (1999): A molecular phylogeny of the pheasants and partridges suggests that these lineages are not monophyletic. Mol. Phylogenet. Evol. 11(1): 38–54. doi:10.1006/mpev.1998.0562 PDF fulltext
* Kimball, Rebecca T.; Braun, Edward L.; Ligon, J. David; Lucchini, Vittorio & Randi, Ettore (2001): A molecular phylogeny of the peacock-pheasants (Galliformes: Polyplectron spp.) indicates loss and reduction of ornamental traits and display behaviours. Biol. J. Linn. Soc. 73(2): 187–198. doi:10.1006/bijl.2001.0536 PDF fulltext
* Kimball, Rebecca T.; Braun, Edward L.; Ligon, J. David; Randi, Ettore & Lucchini, Vittorio (2006): Using molecular phylogenetics to interpret evolutionary changes in morphology and behavior in the Phasianidae. Acta Zoologica Sinica 52(Supplement): 362–365. PDF fulltext
* Mayr, Gerald & Weidig, Ilka (2004): The Early Eocene bird Gallinuloides wyomingensis – a stem group representative of Galliformes. Acta Palaeontologica Polonica 49(2): 211–217. PDF fulltext
* Smith, Edward J.; Shi, Li & Tu, Zhijian (2005): Gallus gallus aggrecan gene-based phylogenetic analysis of selected avian taxonomic groups. Genetica 124(1): 23–32. doi:10.1111/j.1095-8312.2001.tb01356.x (HTML abstract)
* Zelenitsky, Darla K.; Hills, L.V. & Currie, Philip J. (1996): Parataxonomic classification of ornithoid eggshell fragments from the Oldman Formation (Judith River Group; Upper Cretaceous), Southern Alberta. Canadian Journal of Earth Sciences 33(12): 1655–1667. PDF fulltext

* Bent, Arthur C. 1963. Life Histories of North American Gallinaceous Birds, New York: Dover Publications, Inc.
* Eaton, Stephen W. 1992. The Birds of North America: Wild Turkey No. 22. The Academy of Natural Sciences; Washington DC: The American Ornithologists’ Union.
* Forbush, Edward H. 1929. Birds of Massachusetts and Other New England States, Norwood Massachusetts: Norwood press.
* Harrison, Kit and George. 1990. The Birds of Winter, New York: Random House.
* Pearson, T. Gilbert, et al. 1936. Birds of America, New York: Garden City Publishing Company, Inc.
* Peterson, M.J. 2000. The Birds of North America: Plain Chachalaca (Ortalis vetula), No. 550. The Birds of North America, Inc., Philadelphia, PA.
* Robbins, Chandler S. et al. 1966. A Guide to Field Identification: Birds of North America, New York: Golden Press.