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Show Table 5. Waterfowl Breeding Species Breeding pair# Pintail 2,000 Gadwail 40,000 Cinnamon teal 40,000 Mallard < 65,000 Ruddy duck 15,000 Northern redhead 20,000 Northern shoveler 10,000 Canada geese 2,000 The total number of individuals is double the breeding pair number. Migration Waterfowl that are produced elsewhere, typically north of Utah, use marshes and lake as a stopover point during their migration. Up to five million waterfowl migrate through Utah each year. Large numbers of Green- winged teal and Pintail use the lake each summer as a key molting area. They fly from other areas and use the large open water portion of the lake for security and foraging. During the waterfowl molt, the birds are flightless for a 3- 4 week period. Pintail numbers in late summer historically reached about 1,000,000 birds. This is approximately 25 percent of the continental population of these birds. In the 1990s, Pintail populations are about 250,000. Green- wing teal numbers peak at 600,000 during the molting and staging period. Populations of the following species also utilize the lake during migration periods and peak at the following levels: Table 6. Waterfowl Population Numbers Species Peak Population Gadwail 100,000 Cinnamon teal 80,000 Mallard 500,000 Ruddy duck 60,000 Canada geese 50,000 Northern redhead 150,000 Canvasback 50,000 Northern shovelers 100,000 From 7,000 to 11,000 Canada geese annually molt along the west side of Bear River Bay. Wintering populations of waterfowl are dependent upon habitat and climatic conditions, which change yearly. The amount of water which is not frozen and the availability of food are the primary factors governing abundance of birds during the winter. If the winter is severe and most of the marshes are frozen over and relatively deep snows cover the ground, birds migrate south until more favorable conditions are encountered. Mid- winter numbers of ducks range from 10,000- 150,000, depending upon the weather. DWR participates with other states and USFWS in the management of migrating waterfowl. Management of birds that can move in one day from state to state or even between countries require coordinated management. Utah conducts several bird surveys each year to determine population numbers. These counts are coordinated with other states so a continental population can be 77 |
