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Subject: Really a Roseate Tern? [Print This Page]

Author: isaac_chan Time: 28/07/2008 22:01 Subject: Really a Roseate Tern?

Southwestern Waters of Hong Kong 香港西南面海域
2008/7/28
D2x + AF-S VR 300mm + 1.7x (Handheld on boat)

We met a Roseate "like" Tern today.

However, it's having a white forehead....

Seems it's not a juvenile as other juveniles still having grayish plumage, but all other adults are still in breeding plumage.

So, what really is it...?

Add a record photo to show its wings and tail.

[ 本帖最後由 isaac_chan 於 29/07/2008 02:11 編輯 ]

Author: lchunfai Time: 28/07/2008 22:09

I think you are right..Roseate Tern (some are first summer)...Am I correct??

[ Last edited by lchunfai at 28/07/2008 22:10 ]

Author: isaac_chan Time: 29/07/2008 02:11

I'm not sure. I know "香港及華南鳥類" said it's first summer plumage. If we see this in the beginning of breeding season, I think I will believe in this. But now is nearing the end of breeding season....

Author: lchunfai Time: 29/07/2008 12:54

Quote:

Original posted by isaac_chan at 29/07/2008 02:11
I'm not sure. I know "香港及華南鳥類" said it's first summer plumage. If we see this in the beginning of breeding season, I think I will believe in this. But now is nearing the end of breeding season. ...

遲到

Author: jemi Time: 29/07/2008 15:47

I think it's a Roseate Tern, all the features of this bird match with the description, except of the length of its tail streamers.

Olsen KM and Larsson H (1995)* mentioned the Roseate Tern (1st Summer) is similar to very pale Common Tern of similar age, but note dark legs and longer outer tail feathers. Unfortunately, they do not have the information of the 2nd summer plumage, but presumably the plumage would be very similar to adult summer.

Comparing the bill shape and length of the Common Tern and Roseate Tern, the bill of Roseate Tern looks longer and thinner.

*Olsen KM and Larsson H (1995) Terns of Europe and north America, London : Christopher Helm ( Publishers) Limited.

Author: ajohn Time: 30/07/2008 14:10

The dark carpal bar (on the leading edge of the wing) indicates that this is a first summer bird. This would explain why the bird is not in full breeding plumage (pale forehead, dull bill). Other plumage aspects and structure seem right for this to be a Roseate Tern.

Terns usually do not breed in their first summer and rarely return to the breeding grounds at this time (most stay in the wintering areas), which is why this plumage is not usually seen in HK.

A very good set of photos of this interesting bird.

Author: isaac_chan Time: 30/07/2008 17:49

Quote:

原帖由 ajohn 於 2008-7-30 14:10 發表
Terns usually do not breed in their first summer and rarely return to the breeding grounds at this time (most stay in the wintering areas), which is why this plumage is not usually seen in HK.

That's why I have never seen this plumage in the past years....

Thank you.

Author: Allen Time: 30/07/2008 18:59

It came to HK only for travelling, not for breeding. Interesting......

Thanks ajohn for explanation.

Author: Sze Time: 3/08/2008 00:45

Quote:

Original posted by Allen at 30/07/2008 18:59
It came to HK only for travelling, not for breeding. Interesting......

Thanks ajohn for explanation.

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