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U.S. Fish and Wildlife Service, Route 1, Box 877, Morris, MN 56267

Mallard numbers continue to decline. Our best efforts to manage nesting cover and predators to benefit mallards often produce marginal results. Opportunities to expand these programs and impact continental populations are very limited.

Most managers are aware of the impact wood duck boxes have had in boosting the wood duck population. Literature and personal contacts, primarily with Joe Ball, Montana Cooperative Wildlife Research Unit, supported the concept that mallards should readily adapt to over-water nesting structures and experience a high percentage of use and success. It appears, however, little had been done to develop structures adaptable for widespread use by wildlife managers as well as by sportsman's clubs and private landowners.

With these objectives, the Morris Wetland Management District (WMD) began field tests in 1991 with only eight floating structures. After surprising success, the field tests were expanded in 1992 to 32 floating structures which averaged one nest/structure and 81% nest success. Three other new ideas were also field-tested. These included cylinders attached to large round bales and two smaller floating structures. While structure numbers in each test were low, mallard use and success numbers were surprisingly high.

The 1993 field tests were expanded to include nesting cylinders on poles. We have 149 structures with 463 available nests this year. We believe any reasonable variation of the cylinder-shaped structure in an over-water location is likely to be used by mallards.