at the moment, most zoo's keep several animals, but there doesn't seem to be much chemistry between pairs except in paradisio. prague have theirs just as long, I think lowry and SD even longer. the 2 in walsrode can't stand each other from what I've heard.
breeding in the wild is not well documented, but it is believed to be the dry season. during wet season there would be risk of flooding of the nests.
interestingly the paradisio animals also mated last year during the fall, but with no effect.
I do not really believe the actual time of year is important to trigger matings, but more the weather condition. all matings we observed happened during periods of dry hot weather. late spring in 2006. spring AND fall 2007 (probably due to very variable weatherconditions) and this year also during a hot dry period of several weeks. only a week or 2 earlier than in 2006
this of course being just my theory.