Date of this Version
U.S. Fish and Wildlife Service Migratory Birds and State Programs Mountain-Prairie Region Lakewood, Colorado.
Observers counted 4,637 swans (white birds and cygnets) in the Rocky Mountain Population of trumpeter swans during January and February 2008, which essentially was unchanged (-1%) from the 4,701 counted during winter 2007. The numbers of white birds (3,818) increased 4%, but the number of cygnets (808) decreased 12% from counts last year. However, these changes are somewhat biased due to a number of birds in Idaho not being classified as either white birds or cygnets in both 2007 (122 birds) and 2008 (11 birds). In the tri-state area, the number of total swans decreased in Montana (-21%) and Wyoming (-20%), but increased (+8%) in Idaho. The decrease in Wyoming was attributable primarily to a decrease in birds observed at Yellowstone National Park (-57%). The number of birds wintering in areas near restoration flocks was the highest since 1998. The numbers of birds near Summer Lake Wildlife Management Area (WMA) and at Ruby Lake National Wildlife Refuge (NWR) were essentially identical to those of last year, but the number of birds counted at Malheur NWR increased. Reservoir levels in early February were dramatically lower than during winter 2007, and cumulatively were 20% below the long-term average. Generally, temperatures in the tri-state area during winter 2007-08 were colder than average, and precipitation was near average or slightly above.