Wary NORTH AMERICAN WOOD DUCK on Shetland

A drake NORTH AMERICAN WOOD DUCK was discovered this afternoon on Brow Loch on Shetland (Rob Fray et al). It is particularly wary and is consorting with Tufted Ducks. It represents the third record for Shetland following single drakes shot dead at Sae Water, near Voe, on 30th October 1977 and on Fair Isle on 27th November 1979 (Pennington et al, The Birds of Shetland).

April is a classic month for transatlantic wildfowl vagrancy in Britain and Shetland in recent years has attracted a drake Hooded Merganser and often gets Ring-necked Ducks.

What I am trying to find out from a North American perspective is the propensity of Wood Ducks in spring to migrate. Do places like Nova Scotia get overshoots in spring? Is April a month when you would expect Wood Ducks to be returning north? I know that vagrant Wood Ducks are regular on Bermuda in autumn and often remain for the winter departing in spring.

I have previously accepted just ONE record of Wood Duck in Britain - a drake that paused briefly by a North Sea oil rig on 2nd November 2003. There have been many other records but because this is a particularly popular species in captivity and attempts at introduction have been made, virtually all have been dismissed as escapes. In contrast, natural vagrants have occurred in Iceland (at least 4 records) and on the Azores (several) so it is almost certain that natural vagrants are occurring in Britain.

I am also interested to know the most recent population estimates on North American Wood Duck and percentage increases/decreases year-on-year since 2000 if this is known

Looking forward to any correspondence/discussion