By Callie B. Moore, Ryan J. Askren, Douglas C. Osborne, and J. Dale James
Greater white-fronted geese breed across the high Arctic and winter in southern portions of the Pacific, Central, and Mississippi Flyways. Also known as specklebellies, or simply whitefronts, these birds migrate 6,000 miles or more between their breeding and wintering grounds each year. Like populations of light geese (snow and Ross's geese), white-fronted goose numbers have increased over the last several decades. The growth of these Arctic goose populations is partially attributed to the birds' ability to exploit agricultural crops such as rice, corn, and soybeans on migration and wintering areas.
There are two populations of white-fronted geese in North America: the Pacific population (see sidebar) and the midcontinent population. Historically, the majority of the midcontinent population wintered on the coastal marshes and rice fields of south Louisiana and Texas. However, in recent decades these birds have expanded their wintering range north and east. White-fronted geese now winter throughout the Mississippi Alluvial Valley (MAV) but are especially abundant in eastern Arkansas. Why have white-fronted geese moved into the MAV and beyond? What habitats are they using? How much food are they eating? And what do these changes mean for ducks and other waterfowl?
Dr. Douglas Osborne, an associate professor with the University of Arkansas's Agricultural Experiment Station, is working along with his graduate students to answer these questions through research. Former graduate student Ryan Askren wrote his master's thesis on the migration chronology, distribution, and winter habitat selection of midcontinent white-fronted geese. His research tracked the movements of individual birds that were captured and fitted with satellite transmitters along the Arctic coasts of Alaska and Nunavut, Canada. Most of the white-fronted geese that were monitored left their northern breeding grounds in early September and then spent nearly a month staging on the prairies of southern Alberta and Saskatchewan before migrating to their wintering grounds. The majority of the birds wintered in eastern Arkansas, with smaller numbers wintering in Louisiana, Texas, and Mexico. Among Askren's most notable findings was that white-fronted geese spent 25 percent of their feeding time in flooded rice fields, where they could potentially compete for food resources with ducks. He also documented that white-fronted geese arrived in the MAV nearly a month before many puddle duck species. The early arrival of white-fronted geese on their wintering grounds gives the birds a competitive advantage because they are able to exploit the most abundant food resources, specifically waste rice in harvested fields, before other waterfowl arrive.
To learn more about the changing distribution of midcontinent white-fronted geese, master's candidate Callie Moore analyzed band-recovery data reported by hunters. Her research confirmed that there has indeed been a major shift in where white-fronted geese are spending the winter. During the 1970s and '80s, the greatest concentrations of wintering white-fronted geese occurred along the Texas Gulf Coast. The primary distribution of wintering birds shifted into Louisiana around 1995 and then into eastern Arkansas by 2005. These results not only support the hypothesis that white-fronted geese have expanded their winter distribution but also may help explain the factors that have influenced this shift.
Beginning in the mid-1970s, global competition and higher costs led to a decline in rice cultivation in coastal Texas. During the 1980s and '90s, years of severe drought intensified this decline. This limited the food resources available and the amount of winter water on the landscape for white-fronted geese in this area. Conversely, rice production and the acreage of flooded fields increased in the MAV during the same period. These changes in agricultural practices have provided more opportunities for white-fronted geese to meet their energy needs in the MAV than on their traditional Gulf Coast wintering areas.
Former graduate student Ethan Massey, who is now a field biologist with Ducks Unlimited, earned his master's degree by studying the feeding habits of Arctic-nesting geese in the MAV. His research has provided a wealth of information about how the diet and body condition of white-fronted geese change over the winter. By examining the esophagus contents of individual birds, Massey discovered that white-fronted geese feed heavily in flooded and dry rice fields from October through late November, which allows them to store fat reserves to sustain them during winter. The birds then switch to a diet consisting largely of green vegetation during mid- to late winter to increase protein levels before the spring migration.
The relatively rapid shift in the distribution of Arctic geese has raised questions and concerns among waterfowl biologists. Eastern Arkansas, which is widely known as the Duck Capital of the World, is a key wintering area for many species of waterfowl, particularly mallards and other dabbling ducks. One concern is that growing populations of white-fronted and light geese might deplete food resources for ducks in this region. Studies suggest that food availability on the wintering grounds can have a significant impact on waterfowl populations. Specifically, inadequate food supplies may reduce waterfowl survival rates during the winter and prevent the birds from acquiring fat reserves prior to the spring migration, which can impact their reproductive potential.
Aerial surveys conducted on fall staging areas and band-recovery data suggest that the midcontinent population of white-fronted geese currently numbers between 1 million and 2.5 million birds. Given the size of this population, the daily bag limit for white-fronted geese in the Central and Mississippi Flyways was recently increased from two to three birds. Research conducted by Osborne and his graduate students at the University of Arkansas at Monticello will also help guide ongoing habitat conservation planning and delivery to help mitigate any adverse effects that increasing populations of Arctic geese might have on other wintering waterfowl in the MAV. This information, along with knowledge gained from other waterfowl research, will help Ducks Unlimited and its partners ensure that sufficient habitat and food resources are available to support healthy and diverse waterfowl populations in this region for years to come.
Callie B. Moore is a master's candidate at the University of Arkansas at Monticello. Ryan J. Askren is a Ph.D. candidate at the University of Illinois at Urbana-Champaign. Dr. Douglas C. Osborne is associate professor of wildlife at the University of Arkansas at Monticello. And Dr. J. Dale James is director of conservation planning in Ducks Unlimited's Southern Region.
Studying Western White-Fronted Geese
The Pacific Flyway population of greater white-fronted geese has also been on the rise in recent decades. This population has grown from about 100,000 birds in the 1970s to a recent average of approximately 600,000. These birds nest primarily in Alaska's Yukon-Kuskokwim Delta and winter from California's Central Valley to Mexico. Ducks Unlimited will be launching a new study this winter that will examine the impacts that growing numbers of white-fronted geese and other Arctic goose populations are having on waterfowl food availability in rice fields and other key habitats in California's Sacramento Valley.