Argusianus argus argus (Malay Argus); sharing an aviary with Bali Mynahs (Leucopsar rothschildi), Fire-Tufted Barbet (Psilopogon pyrolophus) and Raquet-tailed Treepie (Crypsirina temia). This is the male and he was vocalizing the typical "shout", very nice..
Is this the only subspecies Jurong holds? I saw an Argus Pheasant in the central, walkthrough part of the Asian Aviary, but I don't know which ubspecies it is.
I think this is the bird you saw. Jurong brought in some ladies for this handsome dude recently and decided to confine them in the side aviary to stimulate breeding. Here's a nice video of this male doing a courtship display (not taken by me):
[ame=http://www.youtube.com/watch?v=L6wLilv9xLU]Great Argus Pheasant @ Jurong Bird Park - YouTube[/ame]