hpippen

Southern sea of HK 南部水域
28/09/2008

Please correct me if I am wrong.

Common Tern Juvenile 普通燕鷗幼鳥


Aleutian Tern Juvenile 白腰燕鷗幼鳥

HFCheung

Great work.  These photo is excellent to study the moulting of juveniles away from the breeding ground of juvenile of subspecies of Common Tern in this part of the world and Juvenile Aleutian Tern.  I think your ID is correct.

HF Cheung

ddavid

Great photos. The head pattern of the bird in the first pic (juv tern coming into winter plumage)is more like that of White-winged Black Tern than Common, so I suspect it is this species and not Common Tern. I assume the other bird is Aleutian - although not many people can have had experience of this species in this particular plumage!!

HFCheung

Thanks David.  I had overlook this point on the first photo.
I think the point on Aleutian Tern is very important.  Using the photo that were taken on 28th Sept 2008, I hope someone (for example, Peter and Michelle, Pippen or Sammy) can submit to OBC Forktail on the winter plumage and juvenile plumage of Aleutian Tern.  This species is so rarely seen in winter, one of the problem is that the winter and juvenile plumage are not well known.  In fact, you hardly see any photo of this species away from the breeding ground.  The breeding adult and the very young juvenile are well know, but not the other plumages.

HF Cheung