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Subject: Taiwan Bird ID [Print This Page]

Author: tbob Time: 26/01/2011 13:00 Subject: Taiwan Bird ID

Help needed in ID these 2 birds filmed in Taiwan, sorry for poor quality but it is just a computer screen capture

Bob

Image Attachment: Taiwan 1.jpg (26/01/2011 13:00, 101.03 KB) / Download count 315
http://hkbws.org.hk/BBS/attachment.php?aid=8122

Image Attachment: Taiwan 2.jpg (26/01/2011 13:00, 115.74 KB) / Download count 362
http://hkbws.org.hk/BBS/attachment.php?aid=8123

Author: HKBWS Vicky Time: 26/01/2011 14:38

The 2nd one looks like Brown Shrike to me. How come the color is so pale?
The 1st one is a wagtail? Yellow wagtail but with some kind of albino??

Author: EricB Time: 26/01/2011 18:05

This is a very rare xanthochromic Yellow Wagtail.It is usually a genetic abnormality (like albinism) but occasionally can be dietary.I'm not sure why most of its flight feathers are white but there appears to be some darker feathers in there. It seems a little bit odd if its missing the gene to make melanin ( the dark pigment lost in albinism) why it's eye appears so dark.Either way it's clearly xanthochromic , possibly with a second genetic pigmentary problem.
The shrike is washed out looking because it is leucistic.
Here are a couple of links explaining things
http://en.wikipedia.org/wiki/Xanthochromism
http://en.wikipedia.org/wiki/Leucism
I'd be interested if these birds were found in a cluster( same vague area) - as this would suggest some thing triggering DNA mutation (-like a mild poison or radiation in the environment) affecting the population.As an isolated phenomena leucism is not uncommon but xanthochromism is extremely rare in wild birds.
eRic

[ Last edited by RUWright at 27/01/2011 06:18 ]

Author: tbob Time: 27/01/2011 05:34

Thank you both for the detailed replies, I will check with the person that filmed the birds as to whether it was in the same location

Bob

PS: The birds were filmed within 3 Km of each other

[ Last edited by tbob at 27/01/2011 20:35 ]

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