Yellow wagtail, Awashima JAPAN (1 Viewer)

[unipega13]

Good evening (evening at least in Japan atm)

A birding friend of mine went to Awashima, Japan in the beginning of May.
He encountered a yellow wagtail, but seems to have been troubled by which subspecies it is.

From one side, it seems to have the supercilium, resembling a Western yellow wagtail (Motacilla flava plexa; Motacilla flava thunbergi; シベリアツメナガセキレイ)
However, from the other side, the supercilium is not visible, which then resembles an Eastern yellow wagtail (Motacilla flava macronyx; Motacilla tschutschensis macronyx; キタツメナガセキレイ)

I too am troubled by this, and would love to receive help on the ID.
Thank you in advance for all who comment!

 

[chris butterworth]

It's difficult to say from the photos as they seem to be cropped to the maximum, but there does seem to be a slight supercillium behind the eye on the right hand side of the birds head. I would be tempted to go with thunbergi but, I'm afraid, it would be mainly a guess.

Chris

 

[JANJ]

Hi unipega13.

By the looks of this Motacilla it certainly is that of thunbergi, 'plexa' or macronyx. I wouldn´t mind so much over 'plexa' (synonymised with thunbergi in Pipits (Alström & Mild). The ssp macronyx, which apparently is uncommonly found in Japan on migration and apparently not related to thunbergi on DNA data.

http://bioacoustics.cse.unsw.edu.au/birding-aus/2006-05/msg00300.html
http://orientalbirdimages.org/search.php?Bird_ID=2087&Bird_Image_ID=71275&p=21

http://bird-o.com/2010/06/01/identification-of-australian-yellow-wagtails/

JanJ

 

[unipega13]

Dear Chris,

Thank you for the reply!
I agree with the supercilium on the right side, but the left side seems quite unclear. At times, I begin to see a slight supercilium even on the left side, but it's still quite unclear.

 

[unipega13]

Dear JanJ,

Thank you for the links and explanation on the classifications.
I included the synonyms mainly because even the most updated list on Japan uses the preceding scientific names, meaning the two given birds are still considered subspecies.
The second link you gave explains the same subspecies under 'remarks'.

It gets slightly confusing with differences in scientific names, so apologies on that point.
It may be more clear by restating as a comparison between Western (thunbergi) and Manchurian (macronyx).

 

[MKinHK]

On a balance of probabilities it should be macronyx, which can be pretty variable, and a least in Hong Kong often does not show a supercilium.

CheerS
Mike

 

[unipega13]

Dear Mike,

Apologies on the late reply.
It's difficult to say by probabilities during this season, especially on smaller islands of Japan, since it during the migratory season, when many irregular and accidental visitors appear.
Although, I do agree that this particular bird seems to learn towards macronyx.
Thank you for your comment.