Sunday, 17 March 2013

White-winged Crow - new to science?

 A Carrion Crow - so it seemed....
But then it flew... 
 Exposing nice white wingbars


Birding this morning at The Scrubs produced the interesting sight of a Carrion Crow with white wingbars. When I first saw the bird it was heading low towards me above the grassland. The white on the wing initially startled me. It was only as it flew past me that I suddenly realised that I had a camera - so I started snapping.

In truth, over the years there have been a fair proportion of the crows at The Scrubs that displayed varying degrees of white in their plumage. There was even a ginger individual that frequented the area around the prison for a couple of years.

This was the first bird I had seen with a complete white wingbar and of course, this is no new species but a Carrion Crow with a plumage mutation. But why do crows develop this? And why do I only see these birds in dense urban populations and not in rural districts?

5 comments:

Alan Tilmouth said...

I seem to remember reading it was related to diet, possibly also white bread but I can't remember where I read that.

The Urban Birder said...

I think that I need to do some more research into this subject as I wrote this entry cold.

There has been quite a lot of response to it on Twitter.

Hope you're well Alan.

Warren Baker said...

I read that it is due to a poor diet while the feathers are being formed, sometimes the flight feathers can be barred with pale lines, due to an inconsistent food supply :-)

Dan Burgess said...
This comment has been removed by the author.
Joek Roex said...

We get quite a few of those leucistic Carrion Crows around Bute Park in Cardiff. It's a genetic condition, which I suppose will carry for a few generations and as the black genes are dominant will eventually disappear again from a family gene pool.

If you're ever in Cardiff, I can show you around.