cywong

Mai Po 20/09/09

lpaul

Do you have further photos of the last bird?  There is much to suggest Black Tern on this bird (overall darkness, head pattern, bill structure) although the paler rump favours White-winged.  Do you have photos of the underparts which would resolve the issue?

cywong

Thank you very much for correcting the ID of this bird.

The following photo may belong to the same bird because both photos were taken at 8:35am , but sorry that I am not absolutely sure.

ajohn

Assuming the photo is of the same bird (and I think it probably is), this clinches the ID as White-winged Tern. Note that it still has some black underwing coverts retained from breeding plumage (Whiskered and Black Terns have white underwings)

cywong

Thank you for sharing your expert knowledge on identification of these 3 tern species.