North Iowa becomes a Hen House Super Site

by Lowell Washburn

    Thanks to a cooperative joint venture between the Manitoba, Canada based Delta Waterfowl Foundation, the Iowa DNR, and the Waterfowl Association of Iowa, breeding pairs of mallard ducks will find a noticeable increase in secure nesting sites as they return to Iowa wetlands later this month.
    According to DNR Waterfowl Technician, Al Hancock, the conservation partnership calls for the installation of 500 artificial mallard nesting structures during the next five years. Known as Delta Hen Houses, the structures are an 18-inch diameter, three-foot-long wire cylinder covered in flax straw and lined with softer nesting material. When installed over water, the structures offer a safe haven from egg eating predators such as mink and raccoons. The pilot project is focused on wetlands surrounding Clear Lake and represents the first Hen House Super-Site attempted in Iowa.
    “Right now, we’re in the process of installing the first 100 structures,” said Hancock. “The nests are being placed on public areas, and we’re targeting the smaller prairie pothole-type wetlands that nesting mallards prefer. As the project takes off, we’ll be monitoring those structures for usage and success.”
    During future years, the Iowa DNR will maintain the structures annually by replacing the nesting material, said Hancock.
    In a previous Iowa trial experiment, artificial nesting cylinders received 70 percent use by mallard ducks, and enjoyed a 70 to 87 percent rate of success. The structures are considered to be an effective way to aid in bolstering local mallard populations.