Great argus  (Argusianus argus)

Great argus males are amongst the most unusual and distinctive of all birds, unmistakable with their astoundingly long wing and tail feathers, decoratively adorned with iridescent eye-spots (ocelli) (4). The elongated secondary wing feathers, important for flight in most other birds, have evolved instead for courtship display in this species, to the detriment of flying ability (5). Upperparts of the male are otherwise rusty-brown, finely mottled with intricate buff and black spots (4) (6). Females are similar but smaller than males, with shorter tail and wing feathers and lacking the male's eye-spots (4) (6). Both sexes have conspicuous bare blue facial skin, and a black crown with a short crest (4). The Bornean great argus (A. a. grayi) is slightly smaller than the Malaysian great argus (A. a. argus) and can be distinguished by more burnt-orange colour on its upper breast and neck and whiter spotting on upperparts (2) (4).

The Bornean great argus (A. a. grayi) is native to Borneo (2) (4), while the Malaysian great argus (A. a. argus) can be found on the Malay Peninsula, including south Myanmar, peninsular and southwest Thailand, and Peninsula Malaysia, as well as Sumatra, Indonesia (2) (4) (7).

Inhabits tall, dry, lowland primary and logged forests from sea level up to around 1,300 m, but principally below 900 m (7).

Great argus are solitary for most of the year, except when females visit male courtship arenas to breed (2) (5). Males maintain territories that include dancing grounds for their courtship displays, which they keep clear of leaves, sticks and twigs, and from here they call to advertise their presence to females (2) (6). When a female arrives, the male circles her and spreads his wings into two impressive fans, flaunting hundreds of eye-spots (5). Mating is polygynous, and after mating, females depart to lay two to four eggs in a secluded scrape on the forest floor, where they are incubated for 24 to 25 days, with the male taking no part in nesting, incubation, or rearing of the young (2) (5) (8). Young are quick to become independent and are sexually mature by their third year (8).

These birds roost in trees at night (6) and forage in the leaf-litter of the forest floor by day, feeding on a variety of plant and invertebrate species (2).

Although widespread and fairly numerous, the great argus is in steep decline, particularly in Sumatra, primarily as the result of rapid deforestation and habitat fragmentation in lowland areas across its range (2) (7). Fortunately, the upper elevations of its habitat have not suffered so severely from forest loss, and the species appears to tolerate selectively logged sites. Excessive hunting and trapping are of additional concern, especially in Borneo (7).

The great argus exists in many protected areas across its range, and is protected by Indonesian law (2).

For more information on the great argus see:

• del Hoyo, J., Elliott, A. & Sargatal, J. (1994) Handbook of the Birds of the World - New World Vultures To Guineafowl. Vol. 2. Lynx Edicions, Barcelona.
• Asean Regional Centre for Biodiversity Conservation (ARCBC):
  http://arcbc.org/cgi-bin/abiss.exe/spd?SID=3219133&spd=280&tx=AV

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