By Johann Walker
Ducks Unlimited is dedicated to the vision of wetlands sufficient to fill the skies with waterfowl today, tomorrow, and forever. This vision drives the work of DU’s conservation staff across the continent. And while the goal never changes, DU’s conservation work is constantly evolving in response to new scientific information and the changing needs of waterfowl populations on diverse landscapes across the continent.
Scientific research and monitoring have always provided the objective foundation for DU’s waterfowl conservation efforts. Waterfowl ecologists and managers have long recognized that to effectively sustain waterfowl populations, they need to understand relationships between population dynamics and habitat. For example, one of DU’s highest priority conservation areas is the Prairie Pothole Region (PPR) of the United States and Canada. Several waterfowl species including mallards, pintails, gadwalls, and blue-winged teal reach their highest breeding densities in this wetland-rich region, and more than half of the continental fall flight can be produced in the PPR in some years. But habitat quality and waterfowl breeding success are highly variable within the PPR. The presence of a large number of breeding waterfowl pairs in a particular area doesn’t necessarily guarantee those pairs will produce a large number of ducklings.
To maximize the efficiency of its conservation work, DU must identify and conserve the landscapes where waterfowl are most productive. Analysis has shown that three factors influence mallard populations more than anything else: nest success, survival of breeding hens, and survival of ducklings. Extensive DU research has shown that nest success is consistently higher on landscapes with more permanent grass cover than on more intensively farmed landscapes. And because most hen mortality occurs while the birds are nesting, survival of breeding hens is higher on grassland-dominated landscapes as well. DU research has also found that duckling survival is highest on landscapes with ample shallow wetland habitat during the brood-rearing period. Thus, DU has identified that the most productive landscapes for breeding waterfowl in the PPR are those with a combination of numerous shallow wetlands (to support breeding pairs and broods) and extensive grassland (to provide cover for hens and their nests).