Hi, I'm planning a trip to Singapore early next year. Trip has mainly been spurred on by the arrival of the Spix's Macaws to Jurong. How long would anyone recommend to spend at each of the 4 'zoos' - Jurong, Night Safari, River Safari and Singapore Zoo? We were thinking of doing 2 a day, i.e. Jurong or the Zoo then either River or Night, or vice versa. However we've noticed the River Safari website recommends (or at least suggests) doing all Mandai attractions in one day. Would a day be enough to do all three for zoo enthusiasts? Thanks in advance for any help!