Here is my theory on the lack of
Diving ducks on the reserve.
This autumn it became obvious that a regular passage of Pochard had occurred, although this was less apparent with Tufted. We have never witnessed before so I wonder if this has always happened during September through to November, but we have always assumed that once birds had arrived they stayed all winter and only moved on in extreme weather conditions. With the lack of hard weather to the east, maybe numbers have not yet been supplemented from birds further afield and all the local migrant athya's have now moved on to their wintering grounds. The upton wintering population has not yet arrived, but now the weather is worsening I would expect (hope:eek!
they will soon show up. Last year a very distinctively facially marked female pochard was seen throughout the winter, which indicated that we do have a wintering flock, albeit small in number. We have also seen a dearth of Jack snipe records and as yet no bitterns, which would point to a lack of cold weather movement from the east, although one underlying factor could be at work, this being the low water levels.
The coot and shovelers are holding up their numbers and as pochard and tufted feed on the same items as them, with tufted being omnivorous and pochard vegetarian mostly, then food would not seem to be an issue.
Watch this space
B
John