Light Goose Populations and Distribution
Prior to the 1960s, light geese were largely confined to a few relatively small colonies in the Canadian Arctic and subarctic. Light goose breeding colonies have since expanded in size, and new colonies have been established as populations have increased exponentially. Based on migration and wintering population surveys, lesser snow and Ross's goose numbers in the Mississippi and Central flyways
have increased threefold over the past five decades, from fewer than 1 million birds in the late 1960s to about 3 million birds today. However, recent breeding ground surveys and population estimates using banding and harvest data suggest that light goose numbers are many times larger than these counts indicate. In fact, waterfowl managers now believe that the total light goose population exceeds 15 million lesser snow geese, 1.5 million Ross's geese, and 1 million greater snow geese.
Why have light goose numbers increased so dramatically over the past half century? In simple terms, the birds have benefited from the expansion of agriculture on their migration
and wintering areas, which has provided them with an almost unlimited food supply. This has increased survival, allowing more young birds to reach breeding age and more adults to return to the breeding grounds in better condition, which has increased productivity.
Changes in land use have also altered the migration and wintering distribution of light geese. Historically, these birds made direct migrations from staging areas along the James and Hudson Bay coasts to wintering areas on coastal marshes of the Gulf of Mexico and the Atlantic Ocean, and from western staging areas to the Central Valley of California
. In recent decades, light geese have become more widely distributed as the birds have shifted to a diet largely consisting of waste grain and other agricultural foods during migration and winter. Lesser snow geese are now wintering farther north and over a much greater area than ever before, and Ross's geese have steadily expanded their range eastward over the past few decades. Along the Gulf Coast, decreasing rice production and severe drought in Texas
have resulted in declines in the number of light geese wintering in this region. Many of the birds that once gathered on the rice prairies of southeast Texas are now wintering in eastern Arkansas
and adjoining states where rice production has increased and water is more plentiful.