By Ryan Heiniger and Andy Bishop
The biannual migration of waterfowl across North America is one of nature's greatest spectacles. During the birds' epic transcontinental journeys, many ducks and geese stop to rest and refuel on staging areas such as Nebraska's Rainwater Basin. During the 1980s, the waterfowl management community began to recognize the value of these midcontinent habitats for their role in supporting waterfowl populations, especially during spring migration. Research revealed that female ducks arriving on the breeding grounds with greater fat reserves nested earlier, produced larger clutches of eggs, and demonstrated a greater propensity to renest if their initial nests were lost.
The recognition of "cross-seasonal effects," or the carryover impacts that habitat conditions on wintering and staging areas have on waterfowl when they arrive on the breeding grounds, has transformed waterfowl management. Models have been developed to measure the energetic demands and habitat needs of waterfowl during these critical periods. These models initially helped managers establish habitat conservation goals necessary to support desired waterfowl populations in major wintering areas such as the Gulf Coast, Mississippi Alluvial Valley, and playa lakes region.
More recently, this approach has been applied to guide waterfowl habitat conservation efforts in key staging areas like the Rainwater Basin. Bioenergetics modeling has determined that approximately 62,000 acres of wetlands are needed in this region to provide sufficient foraging habitat to support the estimated 8.6 million waterfowl that annually stop here during spring migration.
As waterfowl migrate north, the birds shift from eating large quantities of waste grain to a diet consisting mainly of native plant foods and invertebrates. Although grain is high in calories, it lacks several key nutrients that waterfowl need for energy and body maintenance. Native "moist-soil" vegetation can produce hundreds of pounds of seeds per acre, providing not only a significant energy source but also the important nutrients not found in waste grain. This balanced diet allows migrating waterfowl to build fat reserves before they return to their breeding grounds in the Prairie Pothole Region, western boreal forest, and the Arctic.
Since the creation of the North American Waterfowl Management Plan (NAWMP)in 1986, wetland conservation efforts in the Rainwater Basin and other midcontinent waterfowl staging areas have primarily focused on providing spring migration habitat for ducks and geese. In a notable shift in focus for waterfowl enthusiasts, the recently revised NAWMP places greater emphasis on conserving wetlands used by ducks and geese during the fall migration. The goal is to provide more opportunities for hunters and other citizens to enjoy this remarkable resource.
Perhaps the most important reason why we must broaden the base of support for wetlands and waterfowl conservation is water. As competition for limited water resources intensifies in the years ahead—especially in arid regions—waterfowl hunters and other conservationists must become more involved in water-allocation decisions and policies. We must all make our voices heard to ensure that wetlands and wildlife are not forgotten when tough decisions are made about how our finite water resources are used.
It's ironic that North America's interior has been referred to by some people as "flyover country." From a waterfowl standpoint, nothing could be further from the truth. In fact, "stopover country" would be a more accurate description, given the importance of midcontinent staging areas to millions of migrating ducks, geese, and other birds. Regardless of where you live, consider paying a visit to the Rainwater Basin or another waterfowl staging area during spring or fall. If you do, you'll understand why these unique habitats are so important to waterfowl and people.
Ryan Heiniger is DU's director of conservation programs in Kansas, Nebraska, Colorado and Wyoming. Andy Bishop is the coordinator of the Rainwater Basin Joint Venture in Nebraska.