Misplaced Pages

Crested argus
Female Vietnamese crested argus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Aves
Order:	Galliformes
Family:	Phasianidae
Tribe:	Pavonini
Genus:	Rheinardia Maingonnat, 1882
Type species
Argus ocellatus Elliot, 1871
Species
R. ocellata R. nigrescens

The Crested argus is a species of large peafowl-like bird in the genus Rheinardia of the pheasant family.

Taxonomy

Although traditionally treated as a single species with two subspecies, it has long been suspected that a species pair is involved and recent evidence, albeit using the controversial Tobias criteria, also supports treating each subspecies as a separate species. The split results in two monotypic species:

Image	Common Name	Scientific name	Distribution
	Malayan crested argus	Rheinardia nigrescens	central Malaysian Isthmus
	Vietnamese crested argus	Rheinardia ocellata	the Annamite mountain range.

The two forms differ significantly in plumage, display and vocalisations and both are threatened by human activity.

Description

Crested arguses have dark-brown-spotted black and buff plumage, a heavy pink bill, brown irises and blue skin around the eyes. The head has two crests; the hind crest, which extends down the occiput, is erected when alarmed and during intentional behaviors including pair bonding and courtship displays. The male has a broad and greatly elongated tail of twelve feathers. The tail covert (or "train") of the male is the longest of any bird and is believed to contain the longest (and widest) feathers to occur in a wild bird; the Reeves's pheasant has tail feathers of similar length but which are considerably narrower. The tail coverts measure up to 1.73 m (5.7 ft) in length, giving the bird a total length of 1.9–2.39 m (6.2–7.8 ft).

The female is similar in size, with a prominent marbled barring and more colourful dorsal plumage than the male. Her conspicuous white facial plumage is like the male, marked with disruptive patterning. The female's crest is different morphologically, with more rigid plumes that take up more surface area along the occiput and upper hind neck. The female's tail is elongated and laterally compressed as is that of the male but of considerably shorter length. The average length of the female is 74–75 cm (2.43–2.46 ft). Despite being sexually dimorphic galliform by length, the male only weighs about 20% more than the female. The average weight is around 1.5 kg (3.3 lb).

The wings of the crested argus are of unusual size and length for its weight. They are wide and square like those of Argusianus versus rounded and abbreviated like those of 'true' pheasants. Additionally, there is no discernible trailing edge secondary wing notch amongst the flight feathers, indicating a capacity of sustained flight in species of this genus. Their wings are morphologically similar to the wings of certain semi-arboreal Craciformes, particularly guans of the genus Pipile. The feet and legs of crested argus are also notable in the presence of curiously developed leg scales in males which are widened in such a matter that they give each limb the appearance of the foreleg of a Varanid lizard. The toes are long and gracile and like other peafowls, the hind toe is less recumbent than those of more strictly terrestrial Galliformes.

Behaviour and ecology

Little is known about them in the wild. Shy and elusive, the crested argus is found in submontane primary forests of Vietnam, Laos and Malaysia in Southeast Asia. The diet consists mainly of invertebrates, mollusks, amphibians, small reptiles, bamboo shoots, leaves, fruits and fungi. Little is known about its reproductive strategy. While it is believed by some authorities to be polygamous, there is no direct evidence to substantiate this theory. Naturalist William Beebe documented pairs of crested argus flying to and from the overstory. This suggests that there may be indefinite pair bonds. There is marked delayed maturity in both species. They appear to be fully adult only in their fifth or sixth year.

The male performs various displays that include serpentine erratic deportment behaviors which include perceptible quill vibration. The lower extremities of the male's wings and tail are pushed vertically into the ground leaving trails in sand and leaf litter. These performances may culminate in the lateral compression of the body and plumage and spreading of his train. The head is held parallel to the ground throughout these display behaviors exhibiting upper throat bristles in one species and downy plumuelles in the second, which together with the forward positioning of the crests, obscure the shape of the head. The male also erects a nuchal hood and hisses audibly while stomping his feet. Like other peafowls, the crested argus employs these and more complex display behaviors in anti-predatory encounters, especially with reptiles.

Habitat and distribution

From limited anecdotal observations of local indigenous peoples, both species select nest sites in elevated reaches, often amongst escarpments on steep slopes amongst leaf litter. They produce very small clutches of from one-two large eggs which are incubated for 25 days. Like other peafowls, crested argus chicks hatch with developed wing feathers. They are bill fed for the first few weeks. In captivity, males also invest in chick rearing, both bill feeding and brooding the chicks both on and off the ground.

Like other peafowl, crested argus retire on emergent trees above the forest canopy for many hours a day. They will remain on these trees for days at a time during the wet season. Crested argus are strong fliers and pairs have been reported flying together.

References

1. "Phasianidae". aviansystematics.org. The Trust for Avian Systematics. Retrieved 2023-08-05.
2. "Species rank for Rheinardia ocellata nigrescens (Phasianidae)". BioOne. 22 June 2020. Retrieved 26 June 2020.
3. "Amazing Bird Records". Trails.com. 27 July 2010. Retrieved 20 October 2011.
4. Biddle, Tami Davis, Pheasants, Partridges, and Grouse : A Guide to the Pheasants, Partridges, Quails, Grouse, Guineafowl, Buttonquails, and Sandgrouse of the World (Princeton Field Guides). Princeton University Press (2002), ISBN 978-0-691-08908-9

v t e Genera of landfowl and their extinct allies
Kingdom: Animalia Phylum: Chordata Class: Aves Superorder: Galloanserae Clade: Pangalliformes
Pangalliformes incertae sedis †Anisolornis? †Archaeophasianus? †Argillipes? †Austinornis? †Chambiortyx †Coturnipes? †"Gigantibis"? †Litoripes? †Percolinus? †Tegulavis? †Gallinuloididae Gallinuloides Paraortygoides †Paraortygidae Paraortyx Pirortyx Scopelortyx Xorazmortyx †Quercymegapodiidae Ameripodius Quercymegapodius Taubacrex †Sylviornithidae Megavitiornis Sylviornis Galliformes See below ↓
Galliformes Galliformes †Amitabha †Bumbanipodius †Bumbanortyx †Linquornis †Namaortyx †Palaeoalectoris †Procrax †Sobniogallus †Taoperdix Megapodiidae †Garrdimalga? †Mwalau †Ngawupodius Alecturini Aepypodius Alectura †Latagallina Leipoa †Progura Talegalla Megapodiini Eulipoa Macrocephalon Megapodius Cracidae †Archaealectrornis †Boreortalis †Palaeonossax †Procrax Penelopinae Aburria Chamaepetes Penelope Penelopina Pipile Cracinae Oreophasis Ortalis Cracini Crax Mitu Nothocrax Pauxi Phasianoidea See below ↓
Phasianoidea Numididae Acryllium Agelastes Guttera Numida †Telecrex Odontophoridae †Miortyx †Nanortyx †Neortyx Ptilopachinae Ptilopachus Odontophorinae Callipepla Colinus Cyrtonyx Dactylortyx Dendrortyx Odontophorus Oreortyx Philortyx Rhynchortyx Phasianidae See below ↓
Phasianidae Phasianidae †Bantamyx †Centuriavis †Diangallus †Eurobambusicola †Lophogallus †Megalocoturnix †Miogallus †Mioryaba †Palaeocryptonyx †Palaeortyx †Panraogallus †Pliogallus †Plioperdix †Rustaviornis †Schaubortyx †Shandongornis †Shanxiornis †Titanoperdix †Tologuica Rollulinae Arborophila Caloperdix Melanoperdix Rhizothera Rollulus Xenoperdix Pavoninae Tropicoperdix Coturnicini Alectoris Ammoperdix Coturnix Margaroperdix †?Ophrysia Perdicula Pternistis Synoicus Tetraogallus Gallini Bambusicola Campocolinus Francolinus Gallus Ortygornis Peliperdix Scleroptila Pavonini Afropavo Argusianus Pavo Rheinardia Polyplectronini Galloperdix Haematortyx Polyplectron Phasianinae †Chauvireria Ithaginis Lerwa Lophophorini Lophophorus Tetraophasis Tragopan Phasianini Catreus Chrysolophus Crossoptilon Lophura Perdix Phasianus Syrmaticus Tetraonini Bonasa Canachites Centrocercus Dendragapus Falcipennis Lagopus Lyrurus Meleagris †Palaealectoris †Proagriocharis Pucrasia †Rhegminornis Tetrao Tetrastes Tympanuchus

• Rheinardia
• Birds of Laos
• Birds of Vietnam
• Birds of the Malay Peninsula