Thanks to all for the help.
Thanks for posting the great picture Iain. Going by that, I am pretty sure it WAS a pair of wood ducks.
Thanks also for the suggestion it may be grouse. We definatly have lots of grouse around here. But looking at pictures of grouse, I think there was too much black and fine white lines for it to be a grouse.
Naturally, I have not seen them since, and look for them every day.