California: Ancestral Wintering Ground
Waterfowl migration can be defined as “the annual spring and fall movement of a population between its breeding and wintering ranges” (Wesley and Leitch, 1987). In general, migratory waterfowl leave their principal breeding grounds in Alaska, the Arctic and Canada in the late summer or fall to “fly south for the winter.” Depending on the species, birds seeking less harsh to warm climates spend their winters in the U.S., Mexico, Central America or South America. In the spring they return instinctively to their ancestral breeding grounds.
In 1935 Frederick C. Lincoln of the Bureau of Biological Survey introduced the “flyway” concept. As a result of extensive waterfowl banding studies, Lincoln recognized what he referred to as “distinct migration corridors” or “lanes of travel” (Hanson and Smith, 1950; Bartonek, 1994). Lincoln showed that ducks and geese strictly adhere to ancestral flight routes. This trait causes them to concentrate over specific regions of the continent as they migrate, as opposed to being more randomly dispersed. Lincoln identified four major regions of concentration and named them the Pacific, Central, Mississippi and Atlantic Flyways (Hanson and Smith, 1950; Flyway Concept, 1955).
California is located within the Pacific Flyway, along with the western states of Alaska, Arizona, Idaho, Nevada, Oregon, Utah and Washington. Ducks and geese using the Pacific Flyway breed and nest primarily in the prairie provinces of Alberta and Saskatchewan, but also to a great extent in Alaska, parts of British Columbia and even Siberia (Flyway Concept, 1955). In the fall Pacific Flyway waterfowl migrate south, keeping west of the continental divide while making their way to wintering grounds in California and Mexico.
California is the main wintering ground for Pacific Flyway waterfowl, with more than 75 percent of the ducks and geese spending at least part of their winters there (Gordon, 1950; Bartonek, 1994). Seven Pacific Flyway migration routes converge at the Tule Lake-Lower Klamath Lake area in northeast California alone — making it the largest flyway concentration area in the United States. From there, the waterfowl move down through the central valley of the state (see Figure 7)
The breeding grounds for Pacific Flyway waterfowl in Alaska and British Columbia suffered far less from drainage and drought than those contributing to the other major flyways. Starting in 1935, drought conditions in the prairie provinces were relieved by increasing rainfall and snowfall. Aquatic vegetation quickly recovered as the lakes filled with water, restoring the waterfowl principle food source. Restoration of the Canadian breeding grounds was further accomplished through the efforts of the Canadian government and Ducks Unlimited.
In the U.S., federal waterfowl refuges were established in eastern Washington, eastern Oregon and northeastern California. Hunting pressure was reduced throughout the western states. First through more restrictive federal regulations which included the outlawing of market hunting, then as a byproduct of U.S. involvement in World War II. These events allowed waterfowl populations in the Pacific Flyway to rebound strongly and by the late 1940s the number of ducks and geese wintering in California numbered 10 million per year (Pacific Waterfowl Flyway Report Number Two, May 1948; Waterfowl Pose California Problem, 1955).
Changes in California’s land use, initiated by white settlers in the mid 1880s, had accelerated over the previous thirty years. The state could no longer accommodate such large numbers of waterfowl without problems arising. By far the most serious problem was depredation to agricultural crops. In other words, wintering waterfowl were eating the farmer’s crops.
Previous to settlers entering California, much of the state’s great central valley extending from present day Chico in the north to Bakersfield in the south consisted of vast marshlands (see Figure 8). The marshes were formed by flooding caused by fall and winter storms and were maintained in the summer by the runoff from melting snow in the Sierra Nevada mountains. For thousands of years Pacific Flyway waterfowl had depended on the marshlands for up to six months out of the year (Gordon, 1952a).
Many of the settlers were farmers. Early development of California’s fertile valleys regulated the flow of water onto the marshes. Flood control projects were built and soon the marshlands were being drained and used for irrigation purposes. As many “reclaimed the land” for farming, the once vast marshlands began to disappear (Gordon, 1952a; Waterfowl Pose California Problem, 1955). Larger and larger segments of the existing waterfowl habitat were taken over for agricultural use.
Many of the ancestral waterfowl areas were turned into rice fields. Rice acreage in California increased from 1,400 in 1912 to 162,000 in 1920 and 485,000 by 1954 (Waterfowl Pose California Problem, 1955). According to an excerpt from a speech by California Wildlife Conservation Board Consultant Seth Gordon in 1952, “[The rice fields] provided choice food and water in the same place. From a duck’s point of view, a rice field is merely an improved marsh; and since the great rice growing districts of the state are located on the sites of some of the best of the original marshes, the birds naturally gravitate to those areas…”
The subsequent losses from duck depredation on rice were enormous, especially when the harvest was delayed. In 1943 alone, ducks ate over $1 million worth of rice. Similarly, widgeon and geese consumed large amounts of fall-planted grains, clover and irrigated pasture grasses, “trampling and puddling what they did not eat” (Gordon, 1952a; Waterfowl Pose California Problem, 1955). During the 1940s the state’s rice industry and the Farm Bureau continuously requested relief from the California Department of Fish and Game (DFG).
Since it was the federal government that regulated the harvest of waterfowl, there was little the DFG could do. The DFG and USFWS representatives attempted to school farmers in “herding” techniques. Herding proved to be a temporary solution at best. Once herded away, if the birds had no comparable place to go and stay — they simply returned.
In the mid 1940s the USFWS achieved promising results with an experimental feeding program. The agency leased several tracts of land, planted them with rice and other cereal grain crops, and then left it all unharvested for the birds. Once herded to these feeding areas, the waterfowl usually stayed. Although successful to a degree, there were too few areas to do the whole job (Waterfowl Pose California Problem, 1955). At about this same time, the DFG started to feel additional pressure from another segment of the population with regard to the waterfowl situation.