Cape Shelduck (South African Shelduck) Tadorna cana
Cape Shelducks are occasionally found in the UK having escaped from captivity. They are superficially similar to Ruddy Shelducks (juveniles are more similar) and are often mistaken as such.
I discovered the following individual among a flock of feral Ruddy Shelducks at Bittering GP and it was subsequently seen at Cley. Please excuse the appalling quality of the photo - it was a long way off and in heavy rain!
Cape Shelduck, Bittering GP (Norfolk, UK), 17th February 2006
The following birds were captive: