Published: 11:33 Monday 25 February 2019
The first thing to say this week is that the bird reported to me was not the one in this picture. However, this was the closest image to what I wanted to show.
A local resident in the Totley area, Joyce Sandford, spotted an unusual bird in her garden and she described it as coloured like a ‘great grey shrike’ or a ‘northern shrike’ that she saw in her identification book. Well, the great grey shrike does visit it us, and it does so in winter too. Furthermore, they do show up on the moors above Dore and Totley to the west of Sheffield. There is a big ‘but’ however, and that is because the great grey shrike is exceedingly rare and most unlikely to come into a garden.
The most likely explanation is not a rare bird but an unusual form of a common one, namely a crow. I have seen albino (i.e. pure white) carrion crows on the peak District moors and they do look most odd. Also, when you get partial or full albinos the effect can totally mask their real identity and even confuse their apparent size. So I wondered if anyone else had seen a white or piebald crow in the area west of Sheffield. The picture I have used is from a visit to Poland a few years ago, where the common crow is the hooded crow or ‘hoodie’ and just shows the potential for variation. The hoodie is really the same species as the carrion crow (or maybe part of a ‘super-species complex’!) but has a more northerly distribution.
They used to occur in England when times were colder in the 1700s and 1800s for example, but have been squeezed northwards and today just occur occasionally in winter. The crow family clearly has the genetic potential to produce predominantly both black plumage and white plumage, and can mix the two.
When these oddball birds turn up then they do grab the attention because they look so strange. Do let me know if you have seen one and better still, send me a picture.
Professor Ian D. Rotherham, of Sheffield Hallam University, researcher, writer and broadcaster on wildlife and environmental issues.