Female Tufted Duck

This photo was taken at Linlithgow Loch, West Lothian during March 2012.
The technical information is as follows.
Camera - Canon EOS 5D Mk II
Shutter speed - 1/640
Aperture - f9.0
Lens - Canon EF 300mm f4.0 L IS USM
Focal Length 300mm
ISO 400