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        Discussion Area 討論區 >> Bird Identification 鳥類辨識 >>  Adult Imperial Eagle 白肩鵰? Common Buzzard 普通鵟??
        
(Message started by: Anguslau on Nov 19^th, 2004, 7:25pm)

Title: Adult Imperial Eagle 白肩鵰? Common Buzzard 普通鵟??
Post by Anguslau on Nov 19^th, 2004, 7:25pm

Can someone please help me to identify these two raptors? Thanks! Photographed this morning at Mai Po.

#1
http://www.pbase.com/anguslau/image/36529982.jpg

#2
http://www.pbase.com/anguslau/image/36529981.jpg

Title: Re: Raptor ID??
Post by Koel_Ko on Nov 19^th, 2004, 7:54pm

First one is an adult Imperial Eagle and second one a Common Buzzard. Looks like you've had quite a good time in MP! ;)

Title: Re: Raptor ID??
Post by Anguslau on Nov 20^th, 2004, 10:32am

Thanks a lot Koel! ;)
Adult and juvenile Imperial Eagles looks so different!

Title: Re: Adult Imperial Eagle 白肩鵰? Common Buzzard 普
Post by Mike Kilburn on Nov 22^nd, 2004, 9:41am

This is a different adult Imperial Eagle from the one I saw in Lam Tsuen.

This means we have at least 3 Imperial and 4 Spotted Eagles (seen by Paul Leader) in Deep Bay so far this winter.

Cheers
Mike

Title: Re: Adult Imperial Eagle 白肩鵰? Common Buzzard 普
Post by Koel_Ko on Nov 24^th, 2004, 5:03am

Mike,
Could you please tell us how to identify the individuals of the eagles, and whether the ones recorded are juveniles or/and adults?
Thanks.

Title: Re: Adult Imperial Eagle 白肩鵰? Common Buzzard 普
Post by Mike Kilburn on Nov 25^th, 2004, 7:55am

I am no expert in raptor ID, but in looking to identify individual birds there are some things you can look for.

a) Moult. I know the adult Imperial Eagle is not the same as the one in Angus' first photo because Angus' bird has complete and evenly feathered wings and tail. On the Lam Tsuen bird the wing looked more ragged, as some of the inner secondaries were growing out to full length. It is also possible to age sub-adult birds which take 3-4 years to adopt adult plumage by moult. There are 2 good books to study this, but be warned - it can be a very complex business:

1) The Macmillan Birder's Guide to European and Middle Eastern Birds (by Harris, Shirihai and Christie 1996 ISBN0333589408) - the identification guide on aquila eagles in this book is enormously detailed - it is the most confusing I have read in any ID guide in 20 years of birding!

2) Flight Identification of European Raptors (by Porter, Willis, Christensen and Nielsen 1974 Third edition 1986 ISBN0856610275)This is an old classic which was the first book to address raptor ID in detail.

There may be other newer book and almost certainly JApanese photo guides, but i do not have these.

b) Wear and tear. Missing or damaged wing and tail feathers can provide a good clue to individual birds, but with time these will be replaced as the bird moults.

c) Size. If you are fortunate like John was, you can see birds side by side - birds are the same as people - different sizes can be told apart (although I think that all 3 juvenile eagles photographed by Angus are Imperial Eagles - (see tht posting for why)

d) Distinguishing features. Some Adult Imperial Eagles have a large amount of white on the shoulders, some very little or none. Others have a heavy yellow "mane" others don't.

e) Simultaneous counting. Eagles travel across Deep Bay in just a few minutes, and can be seen from loger distances than most other birds, so when counting them, recording the time is important if you want to also include birds seen by others in another part of Deep Bay. Otherwise the risk of double counting is high.

f) Site faithfulness. It may help to know if certain birds roost or feed faithfully at the same sites. Pond 20 is the best-known area, but 2 winters ago 2 adult Imperial Eagles were often at Ma Tso Lung in the early morning and roosted nearby. Learnin gsuch things can help you make educated guesses for estimating numbers in the whole of Deep Bay, but cannot give you a confirmed count.

g) Photo analysis. If al the Imperial and Spotted Eagles are photographed it becomes possible to look at small plumage features to identify individual birds, just as Angus has done. Keep shooting!

As for numbers and ages:

I don't know about the Spotted Eagles - I have seen only adult birds, but there may be juveniles too.

There now appear to be at least five Imperials - two adults and three immature or juvenile birds.

Cheers
Mike

Title: Re: Adult Imperial Eagle 白肩鵰? Common Buzzard 普
Post by Etta on Nov 25^th, 2004, 8:59am

Thanks Mike for the guiding, I've learned a lot too! :)

Etta

Title: Re: Adult Imperial Eagle 白肩鵰? Common Buzzard 普
Post by Koel_Ko on Nov 25^th, 2004, 6:43pm

Thanks to Mike for the detailed info. I'd have to look for the books in England as well!