White Wagtail, Taiwan (1 Viewer)

Here is another White Wagtail in Taiwan, which photographed by a local birder today. Is this one M.a. personata or first-winter/adult female alboides ?

Location: Pingtung County, Taiwan.
Date: 24th Feb. 2017

Thanks!

It looks like a personata to me.

I'm not really familiar with the variation in alboides, but do look at a lot of leucopsis, so this assessment is based on the idea that these two black-backed taxa would show similar body/wing pattern.

The rump on your bird is pure grey with black restricted to only a few longest upper tail coverts.
For me, the mantle looks very pale grey for a dark-backed taxon, even a young female (although this variable and can be hard to judge I find).
The greater wing coverts are very extensively white, which would be unusual for a first-winter female, which would usually show some dark centres (at least in leucopsis).
The head pattern is quite advanced into breeding plumage. I've been noticing leucopsis recently moulting into breeding plumage, and the paler first-winter birds are showing obvious contrast in the mantle between paler feathers and replaced darker feathers. Your bird doesn't show any such contrast, which suggests it will be pale-backed in breeding plumage.

Presumably a very unusual record for Taiwan. We've only had a handful of personata in Hong Kong. We still haven't had pure alboides here (only hybirds with leucopsis), and it perhaps is more strictly resident and less prone to vagrancy than personata.

Thanks so much, John.

If so, this personata could be the second record in Taiwan. (The first record is at Dongyin islet, Lienchiang County). And still, we don't have any alboides here so far.

Another question, what's the age and gender? Adult male moulting to his summer plumage?

Thanks!

modrawnu said:

Another question, what's the age and gender? Adult male moulting to his summer plumage?

Click to expand...

Oh dear, you noticed that I had avoided commenting on that :t:

It looks like it has retained secondaries, contrasting with replaced (fresh) tertials. Also retained primary coverts and alula seem to contrast with fresh greater coverts. This suggests to me that it is a first-winter bird which has had a partial post-juvenile moult, whereas I'd expect an adult to show a complete post-breeding moult and have uniform age of all wing feathers.

The very extensive white in the greater coverts and clean grey mantle contrasting with black head suggests to me that it is a male.

So I would say first-winter male moulting into breeding plumage, but I would certainly be interested to hear more opinions about age, gender or ID!

John,

Happy with ID as personata 'Masked' Wagtail and presumably a male.

Here are some images of the UK's first personata that turned in Wales late last year. The moult appears more advanced yet it was aged as a 1st-winter. Apparently in the western ssp at least, ageing in spring using wing-moult can be problematic even in the hand. This may/may not be the same for eastern ssp.

http://joshrjones.blogspot.co.uk/2016/12/masked-wagtail.html

This link has comments re age. Note also the outermost pp appear to be replaced.

http://bretteeblahblahblah.blogspot.co.uk/2016/12/masked-wagtail.html

Just found some more flight shots which don't support my earlier comments re replaced outer pp.

http://www.rarebirdalert.co.uk/v2/Content/2016-Review-A-Year-of-Firsts-Part-5-Late-Winter.aspx?s_id=146011019

Grahame

Thanks for the feedback Grahame. I was not entirely confident about my aging criteria, and I have been told in the past that these are very difficult to age.

It's possible that the contrast between coverts and remiges results from a pre-breeding moult, although Alstrom & Mild state that "In all subspecies, most first-summer birds can be separated by their browner, more worn remiges (especially primaries), primary coverts and often alula", which seems to fit this bird well.