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The Ruddy Dick is a diver and feeds on a variety of plant material and invertebrates which live along the bottom of ponds. The other three species are dabblers, and do not dive but instead "tip up" to a depth equal to the distance between their upper legs and bill tip (approximately 1 - 1.5 feet). Throughout this distance they strain out phyto and zooplankton and also eat a variety of aquatic plants. Given these natural history requirements for the four resident duck species, an ideal pond habitat should conform to the following description: Design: The wetland preserve will be composed of a series of interconnected pond and bay units which vary in size and configuration to provide maximum diversity. Each of the three pond complexes will be engineered to within a 1% grade irrigation plane which receives water every 10-12 days. At this time all ponds will be brought to maximal capacity and the entire riparian plan community within the preserve will be watered. The water will be temporarily held at a depth of 3 to 6 inches at the north end of the preserve for a few days after which it will be pumped back into the B.C.I.D. Canal or into another holding pond on the project site. Depth: Gradually sloping from a six inch initial drop at the shoreline to a maximum of four feet in the center Shape: Moderately irregular so that a maximum amount of shore zone is produced Water: The pond complex should be designed so that a water source at one end of the pond chain will flow through the entire series, thus providing a mild flushing effect. This should take place at approximately one week intervals. The flushing will prevent both eutrophication through algae buildup and botulism, a duck disease which is caused by the accumulation of toxic bacteria (Clostridium botulina) in shallow, stagnant ponds in the Central Valley. Ve etation: Ponds should be planted with a spectrum of soft aquatic plant species characteristic of aquatic habitats in the western Central Valley. A list of same will be presented in the final wetlands management plan. Cattail and tule bullrush should be used sparingly and then only where the management plan calls for it. A riparian woodland planting plan will also be developed once the final design of the wetland is completed. In this plan larger species such as willow and cottonwood will be used to partially screen one small pond from another while still leaving an ample window space for wildlife viewing. 2. Migrant Duck Species The second great worth of such a wetland to waterfowl is that it adds another segment of wintering habitat for over three dozen species of ducks, geese and swans which call the Central Valley their winter home. Many of these species are also dabbling ducks, and thus the small breeding ponds will also serve these winter residents during the non-breed season. However, at least six of our common winter resident duck species are diving ducks which require larger bodies of water for taking off and which can also feed at greater depths. Thus at least two larger ponds should be incorporated into the plan. These should be from 3 to 5 acres in size and contain one or more islands which will serve as resting areas in winter and additional nesting sites in summer. The depth of these large ponds should range from six inches at the shoreline to a maximum of 5 feet at a central deep area between the shore and the island. Like the small ponds, the shoreline of both large ponds and their islands should be irregular and contain several small bay areas. The two large ponds should be connected by a channel, and a water flow system similar to that 37