Great Crested Grebes

This photo was taken at Linlithgow Loch, West Lothian during April 2011.
The technical information is as follows.
Camera - Canon EOS 5D Mk II
Shutter speed - 1/2000
Aperture - f11.0
Lens - Canon EF 500mm f4.0 L IS USM
Focal Length 500mm
ISO 1600