Long Tailed Tit

This photo was taken at Threipmuir Reservoir and Bavelaw near Balerno, during October 2009.
The technical information is as follows.
Camera - Canon EOS 50D
Shutter speed - 1/2500
Aperture - f5.0
Lens - Canon EF 500mm f4.0 L IS USM
Focal Length 500mm
ISO 400