Mallard often stir up little or no interest in birders. Which is a shame, as there are some important questions regarding true numbers of wild birds that need answering.
Mallard take most of their food from the landward side of the seawall- on/around brackish/fresh water, grass or cereal crops. Wide range of feeding techniques for the variety of foods taken. They are mainly nocturnal feeders, so most birds encountered on the estuary are loafers.
Several private feeding areas, maintained by game shooters/wildfowlers, produce the highest numbers at the start and through the winter. It is always difficult to assess how many are 'wild', as some of the shoots release good numbers (in the hundreds) in the month before the start of the shooting season.
Early autumn peak numbers might be expected to remain relatively stable as shot released stock are replaced by incoming continental birds- however numbers close to the seawall do drop away. It is thought that fewer continentals are now migrating, but the result could also easily be down to a more localised effect as more birds spend longer on small waters inland.
The main loafing areas and flightlines are shown below.
From personal experience, the present five year average peak from WeBS totals of 359 for the whole estuary is well below the early winter peak for the southern shoreline. As a mainly nocturnal feeder with a predilection for loafing in small numbers in cover, WeBS timings are really not the best for obtaining maximum counts. The question of true 'wild' numbers is muddied by releases, and co-ordinated counts in late August would certainly give a better indication of totals involved (again, higher than the present five year peak as quoted by WeBS).