Of interest may be a series of excellent photos of a Pied Harrier at Mai Po (in December, I think) taken by 3 different photographers. Link =
http://www.hkwildlife.net/forumdisplay.php?fid=13
Although not strictly comparable - the Pied Harrier is a 1st-calendar year bird - the photos are still very useful. Note the facial pattern, especially the pale areas around the eyes.
I agree with Koel that the photos here are sub-adult male and adult female Eastern Marsh.
David
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Last edited by ddavid at 20/01/2012 21:31 ]