I am a bit puzzled by the identification of this thrush as an Eye-browed Thrush.
This species shows a broader, whiter and longer supercilium than does the bird in the picture.
Secondly, even from this angle an Eye-browed Thrush would show an orange breast and orange flanks.
Grey-sided Thrush is very rare and I think it has never been recorded in Hong Kong.
The bird in the picture looks like a Pale Thrush to me. And I don't see why the legs -- which are actually hard to judge as it comes to their thickness in this picture -- would not fit this species.
The (excellent!) pictures on flickr show a first-winter female Pale Thrush, too.
