US Fish & Wildlife Service
Date of this Version
1-2-2008
Citation
U.S. Fish and Wildlife Service Migratory Birds and State Programs Mountain-Prairie Region Lakewood, Colorado.
Abstract
Observers counted 527 swans (white birds and cygnets) in the U.S. Breeding Segment of the Rocky Mountain Population of trumpeter swans during fall of 2007, 4% higher than the count from last year (507) and the highest count since 1992. The number of white birds in the tri-state region was about the same as in 2006, but the number of cygnets was 40% higher. The numbers of young produced in Montana and Wyoming were 141% and 127% higher, respectively, than those of last year, but the number of young counted in Idaho was 62% lower. The number of cygnets counted in Wyoming this fall was a record high, 20 birds higher than the previous record. The number of white birds counted in Montana was the highest since 1992, but counts in Idaho and Wyoming were 14% and 12% lower, respectively, than counts in 2006. The abundance of birds at Malheur National Wildlife Refuge (NWR) was the lowest recorded since 1967, and no cygnets were counted. No swans were observed at Summer Lake Wildlife Management Area this fall. The count for Nevada was about the same as in recent years. Precipitation thoughout most of the tri-state area was below average during winter 2006-2007. During the summer months, temperatures were 2-6 degrees above average and precipitation was below average, resulting in Palmer Drought Indices for areas within the tri-state region that were somewhat lower than those during summer 2006.
Comments
U. S. government work.