It was a big surprise to me when I went through at night the photos of Common Mergansers I took during the day; I wouldn't imagine there would be a Scaly-sided Merganser mixed with a flock of Common Mergansers (2nd from the right).
Please check again, this level of scales is not enough to be Scaly-sided. Author: Paux Time: 23/12/2011 12:00
Fai Gor, thanks for your comments.
Even though the scales on this Merganser were not so apparent, I think the features of this bird matched the description on 'The Birds of HK & South China' as compared to the Common Mergansers around :
a. Size - 58 cm vs Common Merganser's 65 cm
b. With crest of wispy elongated feathers
c. Different head shape
d. Different side pattern (in flight)
e. Darker feathers around the neck
2 further enlarged photos are attached here for easy reference.