Redheads and white nuns

Another beautiful weekend on the reserve! If you've been stuck indoors have a look at the lovely snowy photos on the website - thanks to everyone who's posted.

Image: Steve Dobromylski

Thanks too for contributing your wildlife sightings to the the community forum and Birdtrack. It's very helpful to us for keeping track of what's about and sharing the information with other visitors.

A highlight from Saturday was a drake (male) smew spotted over Holywell Lake around lunchtime. This striking bird is one of my favourite winter visitors:

Image: Male (foreground) and female smew by Mike Langman (rspb-images.com) 

Usually only 100-200 smews migrate to Britain from Scandinavia and Russia. They end up scattered around the country but with the highest concentration towards the south-east. It's a bird we look out for at Fen Drayton Lakes from November to February - we've enjoyed hosting significant numbers of them in recent years (19 in January 2010, for example).

The interesting thing about their overall migration pattern is that females and juveniles will travel further south and west than the males, so in Britain there are generally only half as many males as females/juveniles.

As Mark Cocker and Richard Mabey point out in their excellent Birds Britannica, this pattern gave the early ornithologists some identification problems.

They would rarely have seen the male and female together and so frequently misinterpreted the birds as two distinct species, leading to a proliferation of names. Sir Thomas Browne, for example, called the female smew the 'weasel coot' because of the reddish-brown head. John Ray later named the male smew the 'white nun' for the drake's white hood. Today the confusion has been cleared up of course but female smews are still sometimes called 'redheads'.

All great names for great birds.