Cast your mind back all of three weeks to the 1st of November, Here, and that odd looking Wagtail on the beach at Boulmer. Today the sighting has really taken off.
Mark Eaton posted some images from yesterday that Ross Ahmed picked up on and
contacted Per Alstrom ( stay with me, I'm almost there) who replied back to
say the bird looked very like a Masked Wagtail x White Wagtail Hybrid. Masked
is from Iran and Kazakhstan and such places.
Needing no further encouragement, I went back on the internet trawling all
over for information and images that might confirm our bird. The more I looked
the more I sank in a mire of confusion and unknown info.
Some images on a Kazakh website looked promising and one from Dubai posted by
Ross looked even better, but none were exactly like our bird. Just similar.
Then I came across a lengthy but readable Dutch paper on the seperation and
identification of Pied Wagtail and White Wagtail. It contained some
encouraging comments -
Wow. If we cant separate European birds that arrive here in good
numbers what chance a Middle Eastern vagrant unless it was a field guide
example.
And on it goes... these birds are really difficult.
Looking at this image above our bird is score 2. 60% chance it is a Pied
Wagtail.Even giving it the benefit and scoring 1, It doesn't look like its come
from very far really.
Then we get to upper tail colour. In my previous blog post at the time the
dark upper tail made it a Pied Wagtail to me, then I was advised that Masked
Wagtail also have dark uppertail coverts. Returning to the paper, there are so
many shades of grey rump a kodak grey colour gradation is required to log them
all.
The Dutch paper goes on -
For some intermediate birds, we do not really know what such birds
are; they were collected far outside the normal range of yarrellii.
They might be the result of interbreeding between alba and another taxon;
in Asia, interbreeding has been recorded with personata, ocularis and
baicalensis (Alström et al 2003) (Per Alstrom again) However, these three taxa show
grey upperparts and rump (without black) in all plumages. In addition, these skins showed white neck sides like alba, while the
combination
alba x personata (the most likely type to occur in Iran, and sometimes
referred to as ‘persica’)
could perhaps be expected to show traces of the dark neck-sides of the latter
taxon. Cramp (1988) also reports occasional black suffusion on mantle,
scapulars and sides of breast in male ‘alba-like birds’, not only from western
but also central Europe far from the breeding range of yarrellii.
So, here we are back to Masked x White Hybrids again, but no one knows what
they really are.
When things get this complicated I wonder about making it simpler. If these
birds readily hybridise, what would a Pied x White look like? Its infinitely
more likely a proposition.
Until I found a page from our now gone great birder, Martin Garner -
Wacky Wagtails
Have a look. He and many others watched a bird on Helgoland in 2007 that looks
like ours. Like me he considered subpersonata. After some thinking and
discussion with top birders like Martin Cade and Gary Woodburn et al they
also provided images like the Boulmer bird, all taken in the UK.
What do these observers think?
They think its a PIED WAGTAIL! Back to my original result.
Oh dear, I think there are some individual creatures out there that will
always have us flummoxed and you know, not all oddities are rare birds. Probably best to leave it as 'alba' wagtail sp... or even sub sp...