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Title: Tern ID please Post by 深藍 Owen on Apr 11th, 2006, 6:48pm Hong Kong South Canon 20D 11/04/2006 http://www.pbase.com/bluetitan/image/58502145.jpg http://www.pbase.com/bluetitan/image/58502144.jpg http://www.pbase.com/bluetitan/image/58502143.jpg |
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Title: Re: Tern ID please Post by David_Diskin on Apr 11th, 2006, 9:19pm I think this is a 1st-summer Common Tern. The combination of white forehead, grey mantle, dark lesser coverts, very worn median and greater coverts, variable dark primaries and short tail streamers point to this. The best reference is probably "Terns of Europe and North America" by Olsen and Larsson (Helm 1995). dave diskin |
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Title: Re: Tern ID please Post by Falcon on Apr 11th, 2006, 11:53pm does juv. have a dark leg colour then the adult?? ??? this one seems to have a very dark leg colour. |
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Title: Re: Tern ID please Post by 深藍 Owen on Apr 12th, 2006, 12:02am on 04/11/06 at 23:53:47, Falcon wrote:
ah yes, according to Birds of HK and SC, seems both common tern adult and juv got no dark leg. |
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Title: Re: Tern ID please Post by David_Diskin on Apr 12th, 2006, 3:12pm So is this Aleutian Tern then? (Note that longipennis Common Terns have black legs). dave diskin |
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Title: Re: Tern ID please Post by Philadelphia on Apr 12th, 2006, 5:10pm http://www.geocities.com/starshinghk/tern.jpg According to Tung, the dark bar on the secondaries revealed the ID of this tern :) |
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Title: Re: Tern ID please Post by Paul Leader on Apr 13th, 2006, 11:40am Assuming this is all the sane bird it is an Aleutian Tern. From the perched pictures it is difficult to get a feel for exactly how dark the upperparts are due to the lighting and the worn plumage. However, the dark bill and feet and the pattern of the dark on the head all point to Aleutian. The flight shot show the classic underwing pattern of Aleutain with the dark trailing on the outer (but not inner primaries) and very obviously across on secondaries. |
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Title: Re: Tern ID please Post by David_Diskin on Apr 13th, 2006, 9:57pm I have no problem with the identification of this bird as an Aleutian Tern - given the last photograph by Philadelphia & Paul's comments. However, based on the initial photos submitted by Owen - as good as they are - I wonder how many birders there are in the world who would be able to say definitively that this is an Aleutian Tern. I'm also a little puzzled as to why this was put on the BBS as Tern ID when YYT had already clearly identified the bird as Aleutian Tern. |
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Title: Re: Tern ID please Post by Yat-tung YU on Apr 13th, 2006, 10:09pm Dave, Actually, I did not see the underwing pattern of the bird very clear when on the boat. I told Philadelphia what features we use to identify Aleutain and Common Terns and strongly suggested him to post his picture on web. Then, let all birdwatchers discuss it and beginner could learn from it as well. Many thanks to your posts and also others Tung |
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Title: Re: Tern ID please Post by David_Diskin on Apr 13th, 2006, 10:26pm Tung - Apologies then. My understanding was that you had definitely identified the bird as Aleutian in the field. Apologies too to Owen if I've written anything that might offend - although I hope that's not the case. His photos are certainly very useful & instructive. I also agree totally with you that these photos should be posted & discussed so that we can all learn from them. I'm certainly learning a lot from the photos and from the comments. dave |
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Title: Re: Tern ID please Post by 深藍 Owen on Apr 13th, 2006, 10:57pm actaully I'm quite disappionted coz I got no common tern photo record but Aleutian already. :( :( |
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Title: Re: Tern ID please Post by David_Diskin on Apr 13th, 2006, 11:00pm I'm sure there are hundreds of bird photographers who wish they could have the same problem!!!! dave |
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