DUD - Duck Use Days

A duck-use day is the measure of which one acre of a given habitat type will provide adequate forage to meet the nutritional requirements of one duck for one day. Put simply, DUD represents the number of ducks that could be supported per day by one acre of habitat type. A variety of research has resulted in the values listed in the DUD table. Areas of standing rice and corn can support many ducks per acre. Once harvested, however, the ability of such areas to sustain numbers of ducks drops tremendously (harvested corn is somewhere below 1,000 DUD/acre). Intensively managed moist-soil units have been shown to produce 11,000-14,000 DUD/acre. Researchers have found that when food densities get too low for efficient feeding (about 45 pounds/acre), that ducks will “give up” on a particular location and move to new areas to feed. 

In comparing the amount and/or quality of forage available to waterfowl in various habitat types, biologists and managers often use the term duck-use days, or Dud. Assuming that the ducks and mallard size and that the daily temperatures are thirty to seventy degrees Fahrenheit, a duck-use day is the measure of which one acre of given habitat type will provide adequate forage to meet the nutritional requirements of one duck for one day. Put simply, DUD represents the number of ducks that could be supported per day by one acre of the habitat type. A variety of research has resulted in the values listed below.

Admittedly, areas of standing rice and corn can support many ducks per acre. Once harvested, however, the ability of such areas to sustain numbers of ducks drop tremendously (harvested corn is somewhere below 1,000 DUD/acre), below that of even average moist-soil. It should be also noted that intensively managed moist-soil areas have been shown to produce figures ranging from 11,000 to 14,000 DUD acre. In addition, researchers have found that when food densities get to low for efficient feeding (about 45pounds/acre), that ducks will “give up” on particular location and move to new areas to feed. This threshold certainly excludes harvested soybean fields from being considered as a choice feeding area for waterfowl.