Ruddy Duck Oxyura jamaicensis
Native to North America, this species established a sizeable feral population in the UK and at its peak became reasonably common in Norfolk, though never so much as in the Midlands. The Iberian population of endangered White-headed Ducks Oxyura leucocephala is perceived to be under threat through hybridisation with British-origin Ruddy Ducks and as a result large-scale culls have taken place within the UK. Consequently Ruddy Duck has nearly been eliminated from the UK, and most birders who do come across them now keep the details secret to prevent them from being shot. The cull proved very controversial, not least because of the manner in which it was conducted - even those of us who are in principle supportive of culling non-native wildlife that poses a threat to native wildlife could not support this fiasco.