I always liked Victoria Peak Garden early in the morning; I went there regularly a few years ago as I worked nearby. The lawns and lawn edges were good for thrushes. I found the area below the car park and and the drop off where there is a low wall at the end of the big lawn was good. The palms drop fruit there and the thrushes would feed. If you approach carefully and sit unobtrusively on the wall you can watch them feed.
Other routes are listed here:
http://www.thepeak.com.hk/en/1_3.asp
Hope that's a help- I haven't been up there for a long time!
Dylan